SB2026061853 - SSRF in phpseclib

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Main Vulnerability Database SB2026061853

SB2026061853 - SSRF in phpseclib

Published: June 18, 2026

Security Bulletin ID SB2026061853
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Information disclosure

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Server-Side Request Forgery (SSRF) (CVE-ID: CVE-2026-55599)

CWE-ID: CWE-918 - Server-Side Request Forgery (SSRF)

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to send attacker-controlled outbound requests to internal services.

The vulnerability exists due to server-side request forgery (SSRF) in X509::validateSignature() when validating an untrusted X.509 certificate. A remote attacker can supply a crafted certificate containing an Authority Information Access URL to send attacker-controlled outbound requests to internal services.

The issue is triggered when the certificate issuer is not already trusted, and the fetched response is handled blindly rather than being exposed directly to the attacker.


Remediation

Install update from vendor's website.

References