CVE-2026-45063: symfony — Fix

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.

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CVSS v3.1 Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0032

Probability of exploitation

0.24%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-290 CWE-290

Affected Products

Vendor	Product	Versions
sensiolabs	symfony	< 5.4.52
sensiolabs	symfony	6.0.0 — 6.4.40
sensiolabs	symfony	7.0.0 — 7.4.12
sensiolabs	symfony	8.0.0 — 8.0.12

References

Advisories & Patches

https://github.com/symfony/symfony/commit/59ef484029601a7af06f5e06c6ed921fdcea5a0d https://github.com/symfony/symfony/security/advisories/GHSA-ph86-p8f6-f9r2

Other References

https://github.com/symfony/symfony/releases/tag/v5.4.52 https://github.com/symfony/symfony/releases/tag/v6.4.40 https://github.com/symfony/symfony/releases/tag/v7.4.12 https://github.com/symfony/symfony/releases/tag/v8.0.12

Frequently Asked Questions

What is CVE-2026-45063? +

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. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2026-45063? +

CVE-2026-45063 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0032, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-45063? +

CVE-2026-45063 affects products from sensiolabs, specifically: symfony. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-45063? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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