# CVE-2026-109449: symfony: In Symfony Expression Language versions prior to 5.4.54, 6.4.48, 7.4.21, and 8.1.9, the parser of the ExpressionLangu...

CVE-2026-109449 is fixed in symfony on 1 platform, first by DEBIAN-CVE-2026-109449, released October 18, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-109449
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0038
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 15, 2026

## Description

In Symfony Expression Language versions prior to 5.4.54, 6.4.48, 7.4.21, and 8.1.9, the parser of the ExpressionLanguage component built its node tree with no bound on its depth. An expression made of tens of thousands of nested unary operators, array literals, binary operators or property accesses crashed the PHP process, while the tree was being freed.   #[Assert\ExpressionSyntax] passes the validated value to ExpressionLanguage::lint(), so an application validating expressions written by its users could be crashed by a single request, and so could any code parsing untrusted expressions.  This issue affects symfony/expression-language through v5.4.53, v6.0.0-BETA1 through v6.4.47, v7.0.0-BETA1 through v7.4.20, and v8.0.0-BETA1 through v8.1.8.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | symfony Debian 13.5 (trixie) | 6.4.49+dfsg-0+deb13u1 | [DEBIAN-CVE-2026-109449](https://patchblox.com/security/data/fix/linux/debian-cve-2026-109449.md) | Oct 18, 2026 |
| Linux | symfony Debian 14 | 7.4.21+dfsg-1 | [DEBIAN-CVE-2026-109449](https://patchblox.com/security/data/fix/linux/debian-cve-2026-109449.md) | Oct 18, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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