CVE-2026-45074 Symfony: Cas2Handler Derives CAS service URL from Client Host Header → Cross-Service Ticket Replay
Attackers can replay CAS tickets to authenticate as victims if trusted hosts are not configured, allowing unauthorized access to Symfony applications.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-45074?
CVE-2026-45074 is a high-severity authentication bypass vulnerability in Sensiolabs Symfony, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-290
Which versions are affected by CVE-2026-45074?
8 open source packages ship an affected version, including symfony/security-http and symfony/symfony. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
symfony/security-http Packagist | From 7.1.0 | 7.4.12 |
symfony/security-http Packagist | From 7.1.0 | 7.4.12 |
symfony/security-http Packagist | From 8.0.0 | 8.0.12 |
symfony/security-http Packagist | From 8.0.0 | 8.0.12 |
symfony/symfony Packagist | From 7.1.0 | 7.4.12 |
symfony/symfony Packagist | From 7.1.0 | 7.4.12 |
2 more packages
symfony/symfony Packagist | From 8.0.0 | 8.0.12 |
symfony/symfony Packagist | From 8.0.0 | 8.0.12 |
Products include Sensiolabs Symfony.
How do I fix CVE-2026-45074?
Upgrade symfony/security-http to a fixed version for your release line: 7.4.12 or 8.0.12.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-45074 being exploited?
There is no known exploitation of CVE-2026-45074 in the wild and no public exploit code.
Other vulnerabilities in Sensiolabs Symfony
Sources
Also known as DEBIAN-CVE-2026-45074, GHSA-j8gj-9rm5-4xhx, UBUNTU-CVE-2026-45074.