PT-2026-44132 · Symfony · Symfony

Published 2026-05-21 · Updated 2026-05-27 · CVE-2026-45063

Positive Technologies (AI Summary)

CVSS v4.0

8.7

High

Base vector

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Name of the Vulnerable Software and Affected Versions Symfony versions prior to 5.4

Description The X509Authenticator component, which implements client-certificate (mTLS) authentication, contains a flaw in how it extracts user identifiers from the Subject DN (Distinguished Name) provided via $ SERVER['SSL CLIENT S DN']. The extraction process uses an unanchored regular expression to find emailAddress=, which allows the pattern to match anywhere within the DN string, including inside the value of a different Relative Distinguished Name (RDN), such as the Common Name (CN). An attacker possessing a certificate from a trusted CA with a free-text CN can insert emailAddress=victim@target into the CN value to be authenticated as the victim.

Recommendations Update to the patched version of branch 5.4.

Exploit

Fix

Authentication Bypass by Spoofing

Weakness Enumeration

CWE-290

Related Identifiers

CVE-2026-45063

GHSA-PH86-P8F6-F9R2

Affected Products

Symfony

References · 13

• 🔥 https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-45063.yaml · Exploit
• 🔥 https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security-http/CVE-2026-45063.yaml · Exploit
• https://osv.dev/vulnerability/GHSA-ph86-p8f6-f9r2 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-45063 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-45063 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-45063 · Security Note
• https://ubuntu.com/security/CVE-2026-45063 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-45063 · Vendor Advisory
• https://github.com/symfony/symfony · Note
• https://github.com/symfony/symfony/commit/ccb3f724c7ff55670a6fe3521c7bf1514cceb478 · Note
• https://github.com/symfony/symfony/security/advisories/GHSA-ph86-p8f6-f9r2 · Note
• https://symfony.com/blog/cve-2026-45063-identity-spoofing-via-unanchored-dn-regex-in-x509authenticator · Note
• https://symfony.com/cve-2026-45063 · Note