CVSS 4.0
2.3 lowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:NCVE-2026-123746 sensiolabs symfony
Low (2.3) in sensiolabs symfony. EPSS 0.3% estimated probability of exploitation activity in the next 30 days.
On this page
The Symfony Security HTTP component AuthenticatorManager::authenticateUser() does not run the firewall user checker’s checkPostAuth() method when a user is authenticated programmatically, allowing an account rejected by a custom user checker, such as an expired account, to be authenticated in Symfony versions prior to 5.4.56, 6.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.
AuthenticatorManager::authenticateUser() is used by UserAuthenticatorInterface::authenticateUser() and by the SecurityBundle’s Security::login() to authenticate a user programmatically, but it does not dispatch the security.authentication.success event, on which checkPostAuth() runs. The fix for CVE-2024-50341 made Security::login() call checkPreAuth(), but checkPostAuth() was still skipped. As a result, an account rejected by a custom user checker in checkPostAuth() is refused by form login and the other authenticators of the firewall, but can still be authenticated programmatically.
Applications are affected when they use a custom user checker that rejects users in checkPostAuth() and authenticate users programmatically, for example after a password reset or an e-mail verification link. A user whose account is rejected can then obtain an authenticated session through that flow. The default user checker does nothing in checkPostAuth(), so the default configuration is not affected.
The fix makes AuthenticatorManager::authenticateUser() dispatch the security.authentication.success event once the token is created and before it is stored, as authentications through the firewall do, so that checkPostAuth() runs and can reject the user.
Severity
- EPSS
- 0.3% estimated probability of exploitation activity in the next 30 days; 21st percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-10. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-288 Authentication Bypass Using an Alternate Path or Channel
- OWASP Top 10
- A07:2025 Authentication Failures
- Published
- Modified
- Assigned by
- Checkmarx (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
Fix and patched versions
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12 | symfony | no fix listed | DEBIAN-CVE-2026-123746 |
| Debian | 13 | symfony | 6.4.50+dfsg-0+deb13u1 | DEBIAN-CVE-2026-123746 |
| Debian | 14 | symfony | 7.4.23+dfsg-1 | DEBIAN-CVE-2026-123746 |
| Ubuntu | 16.04:LTS, 26.04:LTS, 26.10 and 4 more | symfony | no fix listed | UBUNTU-CVE-2026-123746 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.
Attack patterns (CAPEC)
- CAPEC-127 Directory Indexing Likelihood: High · Severity: Medium
- CAPEC-665 Exploitation of Thunderbolt Protection Flaws Likelihood: Low · Severity: Very High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.