Description
An issue was discovered in the HttpFoundation component in Symfony 2.7.x before 2.7.48, 2.8.x before 2.8.41, 3.3.x before 3.3.17, 3.4.x before 3.4.11, and 4.0.x before 4.0.11. The PDOSessionHandler class allows storing sessions on a PDO connection. Under some configurations and with a well-crafted payload, it was possible to do a denial of service on a Symfony application without too much resources.
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 | 3.4.12+dfsg-1 | — |
| Debian 13 | symfony | 3.4.12+dfsg-1 | — |
| Debian 12 | symfony | 3.4.12+dfsg-1 | — |
| Debian 9 | symfony | 2.8.7+dfsg-1.3+deb9u1 | DSA-4262-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | symfony | 3.4.6+dfsg-1ubuntu0.1 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Packagist | symfony/http-foundation | >= 2.7.0, < 2.7.48 | 2.7.48 | GHSA-r2rq-3h56-fqm4 |
| Packagist | symfony/http-foundation | >= 2.8.0, < 2.8.41 | 2.8.41 | GHSA-r2rq-3h56-fqm4 |
| Packagist | symfony/http-foundation | >= 3.3.0, < 3.3.17 | 3.3.17 | GHSA-r2rq-3h56-fqm4 |
| Packagist | symfony/http-foundation | >= 3.4.0, < 3.4.11 | 3.4.11 | GHSA-r2rq-3h56-fqm4 |
| Packagist | symfony/http-foundation | >= 4.0.0, < 4.0.11 | 4.0.11 | GHSA-r2rq-3h56-fqm4 |
| Packagist | symfony/symfony | >= 2.7.0, < 2.7.48 | 2.7.48 | GHSA-r2rq-3h56-fqm4 |
| Packagist | symfony/symfony | >= 2.8.0, < 2.8.41 | 2.8.41 | GHSA-r2rq-3h56-fqm4 |
| Packagist | symfony/symfony | >= 3.3.0, < 3.3.17 | 3.3.17 | GHSA-r2rq-3h56-fqm4 |
| Packagist | symfony/symfony | >= 3.4.0, < 3.4.11 | 3.4.11 | GHSA-r2rq-3h56-fqm4 |
| Packagist | symfony/symfony | >= 4.0.0, < 4.0.11 | 4.0.11 | GHSA-r2rq-3h56-fqm4 |
Advisories 1
- DSA-4262-1 symfony - security update Debian Security (DSA / DLA) · Mar 9, 2026
References
- FEDORA-2018-96d770ddc9 vendor-advisory
- FEDORA-2018-ba0b683c10 vendor-advisory
- FEDORA-2018-eba0006df2 vendor-advisory
- https://symfony.com/blog/cve-2018-11386-denial-of-service-when-using-pdosessionhandler
- DSA-4262 vendor-advisory