Vulnerability · Published Jul 14, 2026 · Assigned by GitHub_M

CVE-2026-45063Symfony: Identity Spoofing via Unanchored DN Regex in X509Authenticator

Critical 9.1

In plain English

A critical-severity authentication bypass by spoofing in symfony from symfony. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)9.1Critical

Exploit odds (30 days)0.3%top 72.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, X509Authenticator extracts the user identifier from $_SERVER['SSL_CLIENT_S_DN'] with an unanchored regex that matches emailAddress= anywhere in the distinguished name, allowing an attacker with a trusted certificate containing emailAddress=victim inside another RDN value such as CN to authenticate as the victim. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	symfony	5.4.53+dfsg-0+deb12u1	DEBIAN-CVE-2026-45063
Debian:13	symfony	6.4.41+dfsg-0+deb13u1	DEBIAN-CVE-2026-45063
Debian:14	symfony	7.4.12+dfsg-1	DEBIAN-CVE-2026-45063
Packagist	symfony/security-http	5.4.52	GHSA-ph86-p8f6-f9r2
Packagist	symfony/security-http	6.4.40	GHSA-ph86-p8f6-f9r2
Packagist	symfony/security-http	7.4.12	GHSA-ph86-p8f6-f9r2
Packagist	symfony/security-http	8.0.12	GHSA-ph86-p8f6-f9r2
Packagist	symfony/symfony	8.0.12	GHSA-ph86-p8f6-f9r2
Packagist	symfony/symfony	5.4.52	GHSA-ph86-p8f6-f9r2
Packagist	symfony/symfony	6.4.40	GHSA-ph86-p8f6-f9r2
Packagist	symfony/symfony	7.4.12	GHSA-ph86-p8f6-f9r2
Ubuntu:25.10	symfony	no fix listed	UBUNTU-CVE-2026-45063
Ubuntu:26.04:LTS	symfony	no fix listed	UBUNTU-CVE-2026-45063
Ubuntu:26.10	symfony	no fix listed	UBUNTU-CVE-2026-45063

Affected products (as reported)

Vendor	Product	Versions
symfony	symfony	< 5.4.52>= 6.0.0-BETA1, < 6.4.40>= 7.0.0-BETA1, < 7.4.12>= 8.0.0-BETA1, < 8.0.12

Weakness: CWE-290 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References

https://github.com/symfony/symfony/security/advisories/GHSA-ph86-p8f6-f9r2 x_refsource_CONFIRM
https://github.com/symfony/symfony/commit/59ef484029601a7af06f5e06c6ed921fdcea5a0d x_refsource_MISC
https://github.com/symfony/symfony/releases/tag/v5.4.52 x_refsource_MISC
https://github.com/symfony/symfony/releases/tag/v6.4.40 x_refsource_MISC
https://github.com/symfony/symfony/releases/tag/v7.4.12 x_refsource_MISC
https://github.com/symfony/symfony/releases/tag/v8.0.12 x_refsource_MISC