Litespeedtech
Monthly
Unauthenticated memory exhaustion in LiteSpeed's lsquic HTTP/3 stack (all versions before 4.9.0) allows a remote attacker to drive a server or client into high memory use and ultimately denial of service by sending header blocks that pile up completed header sets faster than the application claims them, a technique the reporters call a QPACK amplification attack. Any lsquic-based endpoint that exposes HTTP/3 over UDP/QUIC is affected with default settings, since the library applied no cap on buffered header sets; no credentials or user interaction are needed and the vector scores 7.5 (AV:N/AC:L/PR:N/UI:N, availability-only). There is confirmed vendor activity in the form of upstream pull request 666 and the 4.9.0 release notes, and a public research write-up from FoxIO describes the attack class, but no public exploit code was identified at time of analysis and the issue is not in CISA KEV.
Internal redirection URL validation in LiteSpeed Web Server before 6.3.7 build 1 can be bypassed in a narrow 'corner case', allowing an authenticated remote user with low privileges (PR:L per the vendor vector) to have a crafted URL resolve to a resource other than the one the validation logic approved. Because the flaw stems from the URL normalization path decoding the same value more than once (CWE-174), the malformed request passes the check in its first-decoded form but takes on different meaning after a second decode; the assessed impact is high confidentiality loss with only limited integrity impact and no availability loss, with scope crossing into the underlying system. The vendor's CVSS 4.0 vector rates this 9.4 with low attack complexity and all impacts High, whereas our independent assessment (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N) treats exploitation as high complexity because only an undocumented, highly specific corner case triggers it; no public exploit code exists and the issue is not confirmed as actively exploited (CISA KEV), so exposure is limited in practice to attackers who can reach the redirect path and reproduce the exact crafted input.
Stored XSS in the LiteSpeed Cache WordPress plugin (all versions through 7.8.1) allows unauthenticated attackers to permanently inject malicious JavaScript into comment-bearing pages by exploiting a bypass in WordPress's wp_kses sanitizer via decimal numeric character references inside permitted HTML elements. The payload persists in the database and executes in every subsequent visitor's browser, creating session-hijacking, credential-theft, and site-defacement opportunities at scale. No active exploitation is confirmed in CISA KEV, but the changeset between tags 7.8.1 and 7.9 on the WordPress plugin repository confirms a vendor-released fix is available.
Authentication bypass in the LiteSpeed Cache WordPress plugin (versions prior to 6.5.0.1) allows unauthenticated remote attackers to hijack logged-in sessions, including administrator accounts, by recovering weakly protected session credentials. With a 93.13% EPSS score (100th percentile) and publicly available exploit code, this is among the most likely-to-be-exploited vulnerabilities currently tracked. Successful exploitation yields full WordPress site takeover.
Reflected cross-site scripting in the LiteSpeed Cache plugin for WordPress in all versions up to and including 7.9 allows unauthenticated attackers to inject arbitrary script into a page that runs in a victim's browser when the victim is induced to click a crafted link or submit a crafted request. The payload must be delivered as a POST body field named 'esi' while the query string simultaneously carries a validly signed 'esi' value, exploiting PHP's $_REQUEST merge order so the POST value wins at execution; this two-part delivery plus the signature requirement raises attack complexity, and successful exploitation requires user interaction. Impact is limited to the client side (low confidentiality and integrity, no availability impact), giving a CVSS 3.1 base score of 4.7; no public exploit code has been identified at time of analysis and the flaw is not in CISA KEV.
Stored Cross-Site Scripting in LiteSpeed Cache for WordPress (all versions through 7.7) allows authenticated attackers holding Author-level access or higher to inject persistent malicious scripts via specially crafted `<img>` tag attributes. The defect lives in a flawed regular expression inside the plugin's media class that is invoked only when both the 'Lazy Load Images' and 'Add Missing Sizes' features are simultaneously active, causing attribute-embedded payloads to survive sanitization and be stored in page content. Injected scripts execute in the browser of any subsequent visitor, enabling session hijacking, credential theft, or unauthorized actions on their behalf. No public exploit code and no CISA KEV listing have been identified at time of analysis.
LiteSpeed QUIC (LSQUIC) Library before 4.3.1 has an lsquic_engine_packet_in memory leak. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Incorrect Privilege Assignment vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Privilege Escalation.5.1. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
Relative Path Traversal vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Path Traversal.4.1. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Stored XSS.5.0.2. Rated high severity (CVSS 7.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 29.5%.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Stored XSS.5.0.2. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via plugin debug settings in all versions up to, and including, 6.4.1 due to insufficient input sanitization and. Rated medium severity (CVSS 4.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Privilege escalation in LiteSpeed Cache plugin for WordPress (versions up to and including 6.3.0.1) allows unauthenticated remote attackers to forge user identities and gain administrator-level access by exploiting a weak hash check in the plugin's user simulation feature. Publicly available exploit code exists, and the EPSS score of 88.85% (100th percentile) indicates extremely high likelihood of exploitation activity. The vulnerability stems from predictable security hash values that can be brute-forced to impersonate any logged-in user, including administrators.
The LiteSpeed Cache plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 6.2.0.1. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Cross-Site Request Forgery (CSRF) vulnerability could allow attackers to trick authenticated users into performing unintended actions.
OpenLiteSpeed before 1.8.1 mishandles chunked encoding. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Missing Authorization vulnerability in LiteSpeed Technologies LiteSpeed Cache.7. Rated high severity (CVSS 8.2), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Stored cross-site scripting in LiteSpeed Cache for WordPress (versions up to and including 5.7) allows remote unauthenticated attackers to inject persistent malicious scripts that execute in the context of any user - including administrators - visiting affected pages. Publicly available exploit code exists and EPSS scores this at 82.03% (99th percentile), indicating very high probability of opportunistic exploitation across the millions of WordPress sites running this plugin. No CISA KEV listing at time of analysis, but the combination of high EPSS, public POC, and massive install base makes this a priority for WordPress operators.
In LiteSpeed QUIC (LSQUIC) Library before 4.0.4, DCID validation is mishandled. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'esi' shortcode in versions up to, and including, 5.6 due to insufficient input sanitization and output. Rated medium severity (CVSS 6.4), this vulnerability is remotely exploitable, low attack complexity. This Cross-Site Scripting (XSS) vulnerability could allow attackers to inject malicious scripts into web pages viewed by other users.
LiteSpeed OpenLiteSpeed before 1.7.18 does not strictly validate HTTP request headers. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Untrusted Search Path vulnerability in LiteSpeed Technologies OpenLiteSpeed Web Server and LiteSpeed Web Server Container allows Privilege Escalation. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Improper Input Validation vulnerability in LiteSpeed Technologies OpenLiteSpeed Web Server and LiteSpeed Web Server dashboards allows Command Injection. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Directory Traversal vulnerability in LiteSpeed Technologies OpenLiteSpeed Web Server and LiteSpeed Web Server dashboards allows Path Traversal. Rated medium severity (CVSS 5.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
liblsquic/lsquic_qenc_hdl.c in LiteSpeed QUIC (aka LSQUIC) before 3.1.0 mishandles MAX_TABLE_CAPACITY. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This NULL Pointer Dereference vulnerability could allow attackers to crash the application by dereferencing a null pointer.
Privilege Escalation in LiteSpeed Technologies OpenLiteSpeed web server version 1.7.8 allows attackers to gain root terminal access and execute commands on the host system. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A cross-site scripting (XSS) vulnerability in the LiteSpeed Cache plugin before 3.6.1 for WordPress can be exploited via the Server IP setting. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The WebAdmin Console in OpenLiteSpeed before v1.6.5 does not strictly check request URLs, as demonstrated by the "Server Configuration > External App" screen. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The server in LiteSpeed OpenLiteSpeed before 1.5.0 RC6 allows local users to cause a denial of service (buffer overflow) or possibly have unspecified other impact by creating a symlink through which. Rated medium severity (CVSS 6.7), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
The server in LiteSpeed OpenLiteSpeed before 1.5.0 RC6 does not correctly handle requests for byte sequences, allowing an attacker to amplify the response size by requesting the entire response body. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Use-after-free vulnerability in Open Litespeed before 1.3.10. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Cross-site scripting (XSS) vulnerability in service/graph_html.php in the administrator panel in LiteSpeed Web Server 4.1.11 allows remote attackers to inject arbitrary web script or HTML via the. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable. Public exploit code available and no vendor patch available.
Unauthenticated memory exhaustion in LiteSpeed's lsquic HTTP/3 stack (all versions before 4.9.0) allows a remote attacker to drive a server or client into high memory use and ultimately denial of service by sending header blocks that pile up completed header sets faster than the application claims them, a technique the reporters call a QPACK amplification attack. Any lsquic-based endpoint that exposes HTTP/3 over UDP/QUIC is affected with default settings, since the library applied no cap on buffered header sets; no credentials or user interaction are needed and the vector scores 7.5 (AV:N/AC:L/PR:N/UI:N, availability-only). There is confirmed vendor activity in the form of upstream pull request 666 and the 4.9.0 release notes, and a public research write-up from FoxIO describes the attack class, but no public exploit code was identified at time of analysis and the issue is not in CISA KEV.
Internal redirection URL validation in LiteSpeed Web Server before 6.3.7 build 1 can be bypassed in a narrow 'corner case', allowing an authenticated remote user with low privileges (PR:L per the vendor vector) to have a crafted URL resolve to a resource other than the one the validation logic approved. Because the flaw stems from the URL normalization path decoding the same value more than once (CWE-174), the malformed request passes the check in its first-decoded form but takes on different meaning after a second decode; the assessed impact is high confidentiality loss with only limited integrity impact and no availability loss, with scope crossing into the underlying system. The vendor's CVSS 4.0 vector rates this 9.4 with low attack complexity and all impacts High, whereas our independent assessment (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N) treats exploitation as high complexity because only an undocumented, highly specific corner case triggers it; no public exploit code exists and the issue is not confirmed as actively exploited (CISA KEV), so exposure is limited in practice to attackers who can reach the redirect path and reproduce the exact crafted input.
Stored XSS in the LiteSpeed Cache WordPress plugin (all versions through 7.8.1) allows unauthenticated attackers to permanently inject malicious JavaScript into comment-bearing pages by exploiting a bypass in WordPress's wp_kses sanitizer via decimal numeric character references inside permitted HTML elements. The payload persists in the database and executes in every subsequent visitor's browser, creating session-hijacking, credential-theft, and site-defacement opportunities at scale. No active exploitation is confirmed in CISA KEV, but the changeset between tags 7.8.1 and 7.9 on the WordPress plugin repository confirms a vendor-released fix is available.
Authentication bypass in the LiteSpeed Cache WordPress plugin (versions prior to 6.5.0.1) allows unauthenticated remote attackers to hijack logged-in sessions, including administrator accounts, by recovering weakly protected session credentials. With a 93.13% EPSS score (100th percentile) and publicly available exploit code, this is among the most likely-to-be-exploited vulnerabilities currently tracked. Successful exploitation yields full WordPress site takeover.
Reflected cross-site scripting in the LiteSpeed Cache plugin for WordPress in all versions up to and including 7.9 allows unauthenticated attackers to inject arbitrary script into a page that runs in a victim's browser when the victim is induced to click a crafted link or submit a crafted request. The payload must be delivered as a POST body field named 'esi' while the query string simultaneously carries a validly signed 'esi' value, exploiting PHP's $_REQUEST merge order so the POST value wins at execution; this two-part delivery plus the signature requirement raises attack complexity, and successful exploitation requires user interaction. Impact is limited to the client side (low confidentiality and integrity, no availability impact), giving a CVSS 3.1 base score of 4.7; no public exploit code has been identified at time of analysis and the flaw is not in CISA KEV.
Stored Cross-Site Scripting in LiteSpeed Cache for WordPress (all versions through 7.7) allows authenticated attackers holding Author-level access or higher to inject persistent malicious scripts via specially crafted `<img>` tag attributes. The defect lives in a flawed regular expression inside the plugin's media class that is invoked only when both the 'Lazy Load Images' and 'Add Missing Sizes' features are simultaneously active, causing attribute-embedded payloads to survive sanitization and be stored in page content. Injected scripts execute in the browser of any subsequent visitor, enabling session hijacking, credential theft, or unauthorized actions on their behalf. No public exploit code and no CISA KEV listing have been identified at time of analysis.
LiteSpeed QUIC (LSQUIC) Library before 4.3.1 has an lsquic_engine_packet_in memory leak. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Incorrect Privilege Assignment vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Privilege Escalation.5.1. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
Relative Path Traversal vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Path Traversal.4.1. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Stored XSS.5.0.2. Rated high severity (CVSS 7.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 29.5%.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Stored XSS.5.0.2. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via plugin debug settings in all versions up to, and including, 6.4.1 due to insufficient input sanitization and. Rated medium severity (CVSS 4.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Privilege escalation in LiteSpeed Cache plugin for WordPress (versions up to and including 6.3.0.1) allows unauthenticated remote attackers to forge user identities and gain administrator-level access by exploiting a weak hash check in the plugin's user simulation feature. Publicly available exploit code exists, and the EPSS score of 88.85% (100th percentile) indicates extremely high likelihood of exploitation activity. The vulnerability stems from predictable security hash values that can be brute-forced to impersonate any logged-in user, including administrators.
The LiteSpeed Cache plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 6.2.0.1. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Cross-Site Request Forgery (CSRF) vulnerability could allow attackers to trick authenticated users into performing unintended actions.
OpenLiteSpeed before 1.8.1 mishandles chunked encoding. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Missing Authorization vulnerability in LiteSpeed Technologies LiteSpeed Cache.7. Rated high severity (CVSS 8.2), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Stored cross-site scripting in LiteSpeed Cache for WordPress (versions up to and including 5.7) allows remote unauthenticated attackers to inject persistent malicious scripts that execute in the context of any user - including administrators - visiting affected pages. Publicly available exploit code exists and EPSS scores this at 82.03% (99th percentile), indicating very high probability of opportunistic exploitation across the millions of WordPress sites running this plugin. No CISA KEV listing at time of analysis, but the combination of high EPSS, public POC, and massive install base makes this a priority for WordPress operators.
In LiteSpeed QUIC (LSQUIC) Library before 4.0.4, DCID validation is mishandled. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'esi' shortcode in versions up to, and including, 5.6 due to insufficient input sanitization and output. Rated medium severity (CVSS 6.4), this vulnerability is remotely exploitable, low attack complexity. This Cross-Site Scripting (XSS) vulnerability could allow attackers to inject malicious scripts into web pages viewed by other users.
LiteSpeed OpenLiteSpeed before 1.7.18 does not strictly validate HTTP request headers. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Untrusted Search Path vulnerability in LiteSpeed Technologies OpenLiteSpeed Web Server and LiteSpeed Web Server Container allows Privilege Escalation. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Improper Input Validation vulnerability in LiteSpeed Technologies OpenLiteSpeed Web Server and LiteSpeed Web Server dashboards allows Command Injection. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Directory Traversal vulnerability in LiteSpeed Technologies OpenLiteSpeed Web Server and LiteSpeed Web Server dashboards allows Path Traversal. Rated medium severity (CVSS 5.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
liblsquic/lsquic_qenc_hdl.c in LiteSpeed QUIC (aka LSQUIC) before 3.1.0 mishandles MAX_TABLE_CAPACITY. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This NULL Pointer Dereference vulnerability could allow attackers to crash the application by dereferencing a null pointer.
Privilege Escalation in LiteSpeed Technologies OpenLiteSpeed web server version 1.7.8 allows attackers to gain root terminal access and execute commands on the host system. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A cross-site scripting (XSS) vulnerability in the LiteSpeed Cache plugin before 3.6.1 for WordPress can be exploited via the Server IP setting. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The WebAdmin Console in OpenLiteSpeed before v1.6.5 does not strictly check request URLs, as demonstrated by the "Server Configuration > External App" screen. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The server in LiteSpeed OpenLiteSpeed before 1.5.0 RC6 allows local users to cause a denial of service (buffer overflow) or possibly have unspecified other impact by creating a symlink through which. Rated medium severity (CVSS 6.7), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
The server in LiteSpeed OpenLiteSpeed before 1.5.0 RC6 does not correctly handle requests for byte sequences, allowing an attacker to amplify the response size by requesting the entire response body. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Use-after-free vulnerability in Open Litespeed before 1.3.10. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Cross-site scripting (XSS) vulnerability in service/graph_html.php in the administrator panel in LiteSpeed Web Server 4.1.11 allows remote attackers to inject arbitrary web script or HTML via the. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable. Public exploit code available and no vendor patch available.