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CWE-177

Improper Handling of URL Encoding (Hex Encoding)

10 CVEs Avg CVSS 6.7 MITRE
2
CRITICAL
4
HIGH
2
MEDIUM
2
LOW
2
POC
0
KEV

Monthly

CVE-2026-59083 CRITICAL Act Now

Security constraint bypass in Apache Tomcat (8.5.0-8.5.100, 9.0.0.M1-9.0.119, 10.1.0-M1-10.1.56, 11.0.0-M1-11.0.23) lets remote attackers reach protected resources by abusing improperly handled hex URL encoding in the RewriteValve, defeating URL-pattern security constraints. Because the flaw resides in the rewrite valve, only deployments that use the RewriteValve together with security constraints are exposed, but where present an unauthenticated attacker (per CVSS PR:N) can access or manipulate resources meant to be restricted. No public exploit identified at time of analysis, and the issue is not listed in CISA KEV; EPSS data was not provided.

Authentication Bypass Apache Tomcat Apache Tomcat
NVD VulDB
CVSS 3.1
9.1
EPSS
0.2%
CVE-2026-41041 PyPI CRITICAL PATCH Act Now

Improper URL encoding in Apache Gravitino versions 1.0.0 through 1.2.0 lets remote attackers inject crafted path segments through unencoded, user-supplied metadata identifiers, redirecting or manipulating the internal HTTP requests Gravitino issues on the user's behalf. Because the CVSS vector (AV:N/PR:N) indicates no authentication and yields a 9.1 Critical score with high confidentiality and integrity impact, an attacker can potentially reach unintended endpoints, tamper with metadata operations, or exfiltrate data from back-end catalog services. No public exploit identified at time of analysis, and the flaw is fixed in version 1.2.1.

Apache Code Injection Gravitino
NVD
CVSS 3.1
9.1
EPSS
0.2%
CVE-2026-6414 npm MEDIUM PATCH GHSA This Month

@fastify/static versions 8.0.0 through 9.1.0 decode percent-encoded path separators (%2F) before filesystem resolution, while Fastify's router treats them as literal characters. This mismatch allows attackers to bypass route-based middleware or guards that protect files served by @fastify/static. For example, a route guard on a protected path can be circumvented by encoding the path separator in the URL. Upgrade to @fastify/static 9.1.1 to fix this issue. There are no workarounds.

Authentication Bypass Fastify Static
NVD GitHub
CVSS 3.1
5.9
EPSS
0.0%
CVE-2026-29045 npm HIGH PATCH This Week

Hono versions prior to 4.12.4 suffer from an authentication bypass in serveStatic when combined with route-based middleware protections due to inconsistent URL decoding between the router and file serving components. An unauthenticated remote attacker can exploit this mismatch by encoding slashes (%2F) in request paths to access protected static resources that should be restricted by middleware rules. A patch is available in version 4.12.4 and later.

Authentication Bypass Hono
NVD GitHub
CVSS 3.1
7.5
EPSS
0.0%
CVE-2026-22037 npm HIGH PATCH This Week

The @fastify/express plugin prior to version 4.0.3 allows authenticated attackers to bypass path-based middleware restrictions by submitting URL-encoded characters in requests, such as using /%61dmin instead of /admin. While the middleware engine fails to match the encoded path, the underlying Fastify router correctly decodes it and routes the request to handlers, enabling unauthorized access to protected endpoints. This affects Node.js applications using vulnerable versions of the plugin.

Node.js
NVD GitHub
CVSS 3.1
8.4
EPSS
0.1%
CVE-2026-22031 npm HIGH PATCH This Week

Middleware path-matching bypass in @fastify/middie before version 9.1.0 allows authenticated attackers to access protected endpoints by using URL-encoded characters in requests, as the middleware engine fails to decode paths while the underlying router does. An attacker with valid credentials can exploit this inconsistency to circumvent middleware security controls and access restricted functionality. This vulnerability requires low privileges and network access, with no patch currently available.

Authentication Bypass Fastify Middie
NVD GitHub VulDB
CVSS 3.1
8.4
EPSS
0.1%
CVE-2025-11990 LOW Monitor

GitLab has remediated an issue in GitLab EE affecting all versions from 18.4 before 18.4.4, and 18.5 before 18.5.2 that could have allowed an authenticated user to gain CSRF tokens by exploiting. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.

Gitlab CSRF
NVD
CVSS 3.1
3.1
EPSS
0.0%
CVE-2024-48866 LOW Monitor

An improper handling of URL encoding (Hex Encoding) vulnerability has been reported to affect several QNAP operating system versions. Rated low severity (CVSS 2.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Information Disclosure Qnap Qts Quts Hero
NVD
CVSS 4.0
2.3
EPSS
0.4%
CVE-2022-27780 HIGH POC This Week

The curl URL parser wrongly accepts percent-encoded URL separators like '/'when decoding the host name part of a URL, making it a *different* URL usingthe wrong host name when it is later. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Information Disclosure Curl Hci Bootstrap Os Clustered Data Ontap Solidfire Enterprise Sds Hci Storage Node +6
NVD
CVSS 3.1
7.5
EPSS
2.2%
CVE-2018-3718 npm MEDIUM POC PATCH This Month

serve node module suffers from Improper Handling of URL Encoding by permitting access to ignored files if a filename is URL encoded. 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.

Information Disclosure Serve
NVD
CVSS 3.1
5.3
EPSS
1.3%
EPSS 0% CVSS 9.1
CRITICAL Act Now

Security constraint bypass in Apache Tomcat (8.5.0-8.5.100, 9.0.0.M1-9.0.119, 10.1.0-M1-10.1.56, 11.0.0-M1-11.0.23) lets remote attackers reach protected resources by abusing improperly handled hex URL encoding in the RewriteValve, defeating URL-pattern security constraints. Because the flaw resides in the rewrite valve, only deployments that use the RewriteValve together with security constraints are exposed, but where present an unauthenticated attacker (per CVSS PR:N) can access or manipulate resources meant to be restricted. No public exploit identified at time of analysis, and the issue is not listed in CISA KEV; EPSS data was not provided.

Authentication Bypass Apache Tomcat +1
NVD VulDB
EPSS 0% CVSS 9.1
CRITICAL PATCH Act Now

Improper URL encoding in Apache Gravitino versions 1.0.0 through 1.2.0 lets remote attackers inject crafted path segments through unencoded, user-supplied metadata identifiers, redirecting or manipulating the internal HTTP requests Gravitino issues on the user's behalf. Because the CVSS vector (AV:N/PR:N) indicates no authentication and yields a 9.1 Critical score with high confidentiality and integrity impact, an attacker can potentially reach unintended endpoints, tamper with metadata operations, or exfiltrate data from back-end catalog services. No public exploit identified at time of analysis, and the flaw is fixed in version 1.2.1.

Apache Code Injection Gravitino
NVD
EPSS 0% CVSS 5.9
MEDIUM PATCH This Month

@fastify/static versions 8.0.0 through 9.1.0 decode percent-encoded path separators (%2F) before filesystem resolution, while Fastify's router treats them as literal characters. This mismatch allows attackers to bypass route-based middleware or guards that protect files served by @fastify/static. For example, a route guard on a protected path can be circumvented by encoding the path separator in the URL. Upgrade to @fastify/static 9.1.1 to fix this issue. There are no workarounds.

Authentication Bypass Fastify Static
NVD GitHub
EPSS 0% CVSS 7.5
HIGH PATCH This Week

Hono versions prior to 4.12.4 suffer from an authentication bypass in serveStatic when combined with route-based middleware protections due to inconsistent URL decoding between the router and file serving components. An unauthenticated remote attacker can exploit this mismatch by encoding slashes (%2F) in request paths to access protected static resources that should be restricted by middleware rules. A patch is available in version 4.12.4 and later.

Authentication Bypass Hono
NVD GitHub
EPSS 0% CVSS 8.4
HIGH PATCH This Week

The @fastify/express plugin prior to version 4.0.3 allows authenticated attackers to bypass path-based middleware restrictions by submitting URL-encoded characters in requests, such as using /%61dmin instead of /admin. While the middleware engine fails to match the encoded path, the underlying Fastify router correctly decodes it and routes the request to handlers, enabling unauthorized access to protected endpoints. This affects Node.js applications using vulnerable versions of the plugin.

Node.js
NVD GitHub
EPSS 0% CVSS 8.4
HIGH PATCH This Week

Middleware path-matching bypass in @fastify/middie before version 9.1.0 allows authenticated attackers to access protected endpoints by using URL-encoded characters in requests, as the middleware engine fails to decode paths while the underlying router does. An attacker with valid credentials can exploit this inconsistency to circumvent middleware security controls and access restricted functionality. This vulnerability requires low privileges and network access, with no patch currently available.

Authentication Bypass Fastify Middie
NVD GitHub VulDB
EPSS 0% CVSS 3.1
LOW Monitor

GitLab has remediated an issue in GitLab EE affecting all versions from 18.4 before 18.4.4, and 18.5 before 18.5.2 that could have allowed an authenticated user to gain CSRF tokens by exploiting. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.

Gitlab CSRF
NVD
EPSS 0% CVSS 2.3
LOW Monitor

An improper handling of URL encoding (Hex Encoding) vulnerability has been reported to affect several QNAP operating system versions. Rated low severity (CVSS 2.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Information Disclosure Qnap Qts +1
NVD
EPSS 2% CVSS 7.5
HIGH POC This Week

The curl URL parser wrongly accepts percent-encoded URL separators like '/'when decoding the host name part of a URL, making it a *different* URL usingthe wrong host name when it is later. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Information Disclosure Curl Hci Bootstrap Os +8
NVD
EPSS 1% CVSS 5.3
MEDIUM POC PATCH This Month

serve node module suffers from Improper Handling of URL Encoding by permitting access to ignored files if a filename is URL encoded. 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.

Information Disclosure Serve
NVD

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