CVE-2026-45063

Analyzed Analyzed - Analysis Complete

Authentication Bypass in Symfony via X509Authenticator

Publication date: 2026-07-14

Last updated on: 2026-07-15

Assigner: GitHub, Inc.

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-07-14

Last Modified

2026-07-15

Generated

2026-08-04

AI Q&A

2026-07-15

EPSS Evaluated

2026-08-02

NVD

CVE-2026-45063

EUVD

EUVD-2026-44347

Affected Vendors & Products

Vendor	Product	Version / Range
sensiolabs	symfony	From 7.0.0 (inc) to 7.4.12 (exc)
sensiolabs	symfony	From 8.0.0 (inc) to 8.0.12 (exc)
sensiolabs	symfony	to 5.4.52 (exc)
sensiolabs	symfony	From 6.0.0 (inc) to 6.4.40 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-290	This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.

Attack-Flow Graph

Executive Summary

This vulnerability is an identity spoofing issue in Symfony's X509Authenticator. It occurs because the authenticator uses an unanchored regex to extract user identifiers from certificate Distinguished Name (DN) strings. The regex matches 'emailAddress=' anywhere in the DN, including within other components like CN. An attacker can create a certificate with a spoofed email address in the CN field (e.g., 'CN=some name, emailAddress=victim@target') to authenticate as the victim.

Detection Guidance

Check Symfony version with composer show symfony/symfony or php vendor/bin/symfony console about. If using 5.4.x, 6.4.x, 7.4.x, or 8.0.x and version is below 5.4.52, 6.4.40, 7.4.12, or 8.0.12 respectively, the system is vulnerable. Inspect authentication logs for unusual certificate-based logins where CN contains emailAddress=.

Impact Analysis

An attacker could exploit this to authenticate as another user, gaining unauthorized access to sensitive data or functions. This could lead to data breaches, privilege escalation, or compliance violations depending on the system's use case.

Compliance Impact

This vulnerability could lead to unauthorized access to personal data, violating GDPR's data protection principles or HIPAA's access controls. Organizations using affected Symfony versions may face compliance failures and potential penalties.

Mitigation Strategies

Upgrade Symfony to versions 5.4.52, 6.4.40, 7.4.12, or 8.0.12 or later immediately. Review and revoke any certificates with free-text CN fields containing emailAddress= values. Monitor authentication logs for suspicious activity.

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