What’s Vulnerable › Vulnerabilities

CVE-2026-45074: Symfony: Cas2Handler Derives CAS service URL from Client Host Header → Cross-Service Ticket Replay

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-14 · updated 2026-07-15
• Weakness: CWE-290

Description

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 7.1.0 until 7.4.12 and 8.0.12, Cas2Handler builds the CAS service parameter from Request::getSchemeAndHttpHost(), which reflects an attacker-controlled Host header when framework.trusted_hosts is not configured; an attacker controlling another application registered with the same CAS server can replay a victim ticket against the Symfony application and authenticate as the victim. This issue is fixed in versions 7.4.12 and 8.0.12.

Affected products

• symfony: from 7.1.0 before 7.4.12; from 8.0.0 before 8.0.12 — fixed in 7.4.12, 8.0.12

How to fix

Upgrade to a fixed version: symfony 7.4.12, 8.0.12. Check the vendor advisory for mitigations.

References

• https://github.com/symfony/symfony/commit/5ba145dba702404801bdf9e7e8d6df170060d541
• https://github.com/symfony/symfony/releases/tag/v7.4.12
• https://github.com/symfony/symfony/releases/tag/v8.0.12
• https://github.com/symfony/symfony/security/advisories/GHSA-j8gj-9rm5-4xhx

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