Description
The attemptAuthentication function in Component/Security/Http/Firewall/UsernamePasswordFormAuthenticationListener.php in Symfony before 2.3.41, 2.7.x before 2.7.13, 2.8.x before 2.8.6, and 3.0.x before 3.0.6 does not limit the length of a username stored in a session, which allows remote attackers to cause a denial of service (session storage consumption) via a series of authentication attempts with long, non-existent usernames.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | symfony | 2.8.6+dfsg-1 | — |
| Debian 13 | symfony | 2.8.6+dfsg-1 | — |
| Debian 12 | symfony | 2.8.6+dfsg-1 | — |
| Debian 8 | symfony | 2.3.21+dfsg-4+deb8u3 | DSA-3588-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | symfony | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Packagist | symfony/security | >= 2.3.0, < 2.3.41 | 2.3.41 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/security | >= 2.4.0, < 2.7.13 | 2.7.13 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/security | >= 2.8.0, < 2.8.6 | 2.8.6 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/security | >= 3.0.0, < 3.0.6 | 3.0.6 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/security-http | >= 2.3.0, < 2.3.41 | 2.3.41 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/security-http | >= 2.4.0, < 2.7.13 | 2.7.13 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/security-http | >= 2.8.0, < 2.8.6 | 2.8.6 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/security-http | >= 3.0.0, < 3.0.6 | 3.0.6 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/symfony | >= 2.3.0, < 2.3.41 | 2.3.41 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/symfony | >= 2.4.0, < 2.7.13 | 2.7.13 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/symfony | >= 2.8.0, < 2.8.6 | 2.8.6 | GHSA-whgv-8cg3-7hcm |
| Packagist | symfony/symfony | >= 3.0.0, < 3.0.6 | 3.0.6 | GHSA-whgv-8cg3-7hcm |
Advisories 1
- DSA-3588-1 symfony - security update Debian Security (DSA / DLA) · Mar 9, 2026