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Medium

Symfony's Cas2Handler Derives CAS service URL from Client Host Header → Cross-Service Ticket Replay

  • Disclosed: 27.05.2026
  • Updated: 11.10.2026 10:22

Cas2Handler builds this service parameter from Request::getSchemeAndHttpHost(), which reflects the attacker-controlled HTTP Host header whenever Symfony's framework.trusted_hosts setting is not configured (the default). An attacker who controls any other application registered with the same CAS server can replay a victim's ticket against the Symfony application, with a spoofed Host header, and be authenticated as that victim.

Resolution

A new required service_url configuration option is introduced on Cas2Handler. The CAS service parameter sent to the validation endpoint is now built from this configured URL instead of being derived from the request's Host header, preventing cross-service ticket replay via Host header spoofing.

The patch for this issue is available here for branch 7.4.

Credits

Symfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and Nicolas Grekas for providing the fix.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package symfony/security-http >= 7.1.0, < 7.4.12, >= 8.0.0, < 8.0.12 7.4.12, 8.0.12
Composer package symfony/symfony >= 7.1.0, < 7.4.12, >= 8.0.0, < 8.0.12 7.4.12, 8.0.12

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U
Weakness (CWE)
CWE-290
Platform
Composer
Package
symfony/security-http, symfony/symfony
Disclosed
27.05.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-j8gj-9rm5-4xhx - CC BY 4.0

Vulnerability history: symfony/security-http

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (20) in the archive
Total entries
20
First → latest
12.2019 06.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 10
  • Medium 8
  • Low 2

Disclosures per year

Severity:
  1. Symfony: Security Firewall Bypass via failure_forward Subrequest: Unauthenticated Access to access_control-Protected GET Routes
    High CVE-2026-48489 < 5.4.53, >= 6.0.0, < 6.4.41, >= 7.0.0, < 7.4.13, >= 8.0.0, < 8.0.13 5.4.53, 6.4.41, 7.4.13, 8.0.13
  2. Symfony's HEAD Request Bypasses methods: ['GET'] Filter in #[IsGranted] / #[IsSignatureValid] / #[IsCsrfTokenValid]
    High CVE-2026-45075 >= 7.4.0, < 7.4.12, >= 8.0.0, < 8.0.12 7.4.12, 8.0.12
  3. Symfony's Cas2Handler Derives CAS service URL from Client Host Header → Cross-Service Ticket Replay this entry
    Medium CVE-2026-45074 >= 7.1.0, < 7.4.12, >= 8.0.0, < 8.0.12 7.4.12, 8.0.12
  4. Symfony Vulnerable to Identity Spoofing via Unanchored DN Regex in X509Authenticator
    High CVE-2026-45063 < 5.4.52, >= 6.0.0-BETA1, < 6.4.40, >= 7.0.0-BETA1, < 7.4.12, >= 8.0.0-BETA1, < 8.0.12 5.4.52, 6.4.40, 7.4.12, 8.0.12
  5. Symfony has an Authentication Bypass via RememberMe
    High · 7.5 CVE-2024-51996 >= 5.3.0, < 5.4.47, >= 6.0.0-BETA1, < 6.4.15, >= 7.0.0-BETA1, < 7.1.8 5.4.47, 6.4.15, 7.1.8
  6. Symphony Denial of Service Via Overlong Usernames
    High · 7.5 CVE-2016-4423 >= 2.3.0, < 2.3.41, >= 2.4.0, < 2.7.13, >= 2.8.0, < 2.8.6, >= 3.0.0, < 3.0.6 2.3.41, 2.7.13, 2.8.6, 3.0.6
  7. Symfony Vulnerable to Timing Attack
    High CVE-2015-8125 >= 2.4.0, < 2.6.12, >= 2.7.0, < 2.7.7 2.6.12, 2.7.7
  8. Symfony Session Fixation Vulnerability
    High · 8.1 CVE-2018-11385 >= 2.7.0, < 2.7.48, >= 2.8.0, < 2.8.41, >= 3.0.0, < 3.3.17, >= 3.4.0, < 3.4.11, >= 4.0.0, < 4.0.11 2.7.48, 2.8.41, 3.3.17, 3.4.11, 4.0.11
  9. Symfony CSRF Token Fixation
    High · 8.8 CVE-2018-11406 >= 2.7.0, < 2.7.48, >= 2.8.0, < 2.8.41, >= 3.0.0, < 3.3.17, >= 3.4.0, < 3.4.11, >= 4.0.0, < 4.0.11 2.7.48, 2.8.41, 3.3.17, 3.4.11, 4.0.11
  10. Firewall configured with unanimous strategy was not actually unanimous in Symfony
    High · 7.6 CVE-2020-5275 >= 4.4.0, < 4.4.7, >= 5.0.0, < 5.0.7 4.4.7, 5.0.7
  11. Improper authentication in Symfony
    High · 7.5 CVE-2019-10911 >= 2.7.0, < 2.7.51, >= 2.8.0, < 2.8.50, >= 3.0.0, < 3.4.26, >= 4.0.0, < 4.1.12, >= 4.2.0, < 4.2.7 2.7.51, 2.8.50, 3.4.26, 4.1.12, 4.2.7

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