EUVD-2026-38348Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Network-delivered crafted certificate, no auth or interaction required (PR:N/UI:N); scope change (S:C) reflects SSRF reaching internal systems; confidentiality limited to probing, not direct exfiltration.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
3DescriptionCVE.org
phpseclib is a PHP secure communications library. From 0.1.1 until 1.0.30, 2.0.55, and 3.0.54, when an application validates an untrusted X.509 certificate with phpseclib, X509::validateSignature() reads a URL out of that certificate's Authority Information Access (AIA) extension and connects to it. Attacker who supplies certificate fully controls host, port, and path of that connection. URL fetching is enabled by default, and no destination is blocked. An unauthenticated attacker can therefore make a validating server open connections to internal hosts and ports it should never reach, for example loopback 127.0.0.1, cloud metadata address 169.254.169.254, and internal-only services. This is a server-side request forgery (SSRF) caused by an insecure default. This vulnerability is fixed in 1.0.30, 2.0.55, and 3.0.54.
AnalysisAI
Server-side request forgery in phpseclib's X.509 validation allows unauthenticated network attackers to force the validating server to open arbitrary outbound connections to attacker-controlled hosts, including internal loopback addresses (127.0.0.1) and cloud metadata endpoints (169.254.169.254). The flaw exists because X509::validateSignature() unconditionally fetches URLs embedded in the Authority Information Access extension of untrusted certificates with no blocklist or destination filtering - and this behavior is enabled by default across all three maintained release branches. No CISA KEV listing exists at time of analysis, and no weaponized public exploit was referenced, though the GitHub advisory provides exact file and line references making the trigger path immediately reproducible.
Technical ContextAI
phpseclib (composer package phpseclib/phpseclib) is a pure-PHP cryptographic library providing TLS, SSH, and X.509 certificate operations. The root cause (CWE-918, Server-Side Request Forgery) lies in the certificate chain-building logic: when validateSignatureCountable() cannot find a trusted CA for the certificate under validation, it calls testForIntermediate(), which reads the caIssuers field from the certificate's Authority Information Access (AIA) OID extension and passes that value directly to the internal fetchURL() method. The URL originates entirely from attacker-controlled certificate content and is never sanitized - no blocklist for RFC-1918 ranges, loopback, link-local (169.254.0.0/16), or restricted ports exists in fetchURL(). The disable_url_fetch flag that would suppress this behavior defaults to false, meaning every phpseclib deployment validating untrusted certificates is exposed unless explicitly hardened. Affected CPE: cpe:2.3:a:phpseclib:phpseclib:*:*:*:*:*:*:*:* across branches 1.x (≤1.0.29), 2.x (≤2.0.54), and 3.x (≤3.0.53), with the 4.0 development line also confirmed vulnerable per commit 74ada1a6 in GHSA-m557-wrgg-6rp4.
RemediationAI
Upgrade phpseclib to the patched release corresponding to the branch in use: 1.0.30 for the 1.x branch, 2.0.55 for the 2.x branch, or 3.0.54 for the 3.x branch, as confirmed by the vendor advisory at https://github.com/phpseclib/phpseclib/security/advisories/GHSA-m557-wrgg-6rp4. If an immediate upgrade is not feasible, explicitly set the disable_url_fetch flag to true on all X509 instances before calling validateSignature() - this disables AIA-driven outbound fetching, but as a trade-off, any certificate chain that requires fetching intermediate CAs at runtime will fail validation, necessitating pre-loading all expected intermediate certificates into the trust store manually. As a defense-in-depth layer independent of patching, enforce egress filtering on the PHP application host to block outbound connections to RFC-1918 private ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16), loopback (127.0.0.0/8), and link-local ranges (169.254.0.0/16); this limits SSRF blast radius against internal infrastructure and cloud metadata services but does not prevent SSRF to external attacker-controlled hosts.
In PHP versions 7.1.x below 7.1.33, 7.2.x below 7.2.24 and 7.3.x below 7.3.11 in certain configurations of FPM setup it
sapi/cgi/cgi_main.c in PHP before 5.3.12 and 5.4.x before 5.4.2, when configured as a CGI script (aka php-cgi), does not
(1) boardData102.php, (2) boardData103.php, (3) boardDataJP.php, (4) boardDataNA.php, and (5) boardDataWW.php in Netgear
The '/common/download_agent_installer.php' script in the Quest KACE System Management Appliance 8.0.318 is accessible by
ProjectSend versions prior to r1720 are affected by an improper authentication vulnerability. Rated critical severity (C
Roundcube Webmail contains a critical PHP object deserialization vulnerability (CVE-2025-49113, CVSS 9.9) that allows au
Util/PHP/eval-stdin.php in PHPUnit before 4.8.28 and 5.x before 5.6.3 allows remote attackers to execute arbitrary PHP c
Palo Alto Networks PAN-OS management web interface contains an authentication bypass allowing unauthenticated attackers
Nagios XI version xi-5.7.5 is affected by OS command injection. Rated high severity (CVSS 8.8), this vulnerability is re
Nagios XI version xi-5.7.5 is affected by OS command injection. Rated high severity (CVSS 8.8), this vulnerability is re
The get_referers function in /opt/ws/bin/sblistpack in Sophos Web Appliance before 3.7.9.1 and 3.8 before 3.8.1.1 allows
The Backup Migration plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 1
Same weakness CWE-918 – Server-Side Request Forgery (SSRF)
View allShare
External POC / Exploit Code
Leaving vuln.today