CVE-2026-109449 Affecting symfony package, versions <6.4.49+dfsg-0+deb13u1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-ECHOLATEST-SYMFONY-21185088
- published18 Oct 2026
- disclosed15 Oct 2026
Introduced: 15 Oct 2026
NewCVE-2026-109449 (opens in a new tab)How to fix?
Upgrade Echo:latest symfony to version 6.4.49+dfsg-0+deb13u1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream symfony package and not the symfony package as distributed by Echo.
See How to fix? for Echo:latest relevant fixed versions and status.
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.
References
- https://advisory.echohq.com/cve/CVE-2026-109449
- https://github.com/symfony/symfony/pull/65690
- https://github.com/symfony/symfony/pull/66720
- https://github.com/symfony/symfony/pull/66723
- https://github.com/symfony/symfony/security/advisories/GHSA-7rpj-w9pf-39rr
- https://symfony.com/blog/cve-2026-109449-unbounded-nesting-in-the-expression-parser-lets-untrusted-expressions-crash-the-process