Server-side Request Forgery (SSRF) Affecting phpseclib/phpseclib package, versions >=0.1.1, <1.0.30>=2.0.0, <2.0.55>=3.0.0, <3.0.54
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-PHP-PHPSECLIBPHPSECLIB-17420054
- published23 Jun 2026
- disclosed22 Jun 2026
- creditEvidentObscurity
Introduced: 22 Jun 2026
NewCVE-2026-55599 (opens in a new tab)How to fix?
Upgrade phpseclib/phpseclib to version 1.0.30, 2.0.55, 3.0.54 or higher.
Overview
phpseclib/phpseclib is a PHP Secure Communications Library - Pure-PHP implementations of RSA, AES, SSH2, SFTP, X.509 etc.
Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) via the X509::validateSignature() function that follows a URL from Authority Information Access (AIA) extension without validation. An attacker can cause the server to initiate arbitrary outbound network connections by supplying a crafted X.509 certificate containing a malicious AIA extension.