| Name | CVE-2026-109449 |
| 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| symfony (PTS) | bookworm, bookworm (security) | 5.4.53+dfsg-0+deb12u1 | vulnerable |
| trixie (security), trixie | 6.4.41+dfsg-0+deb13u1 | vulnerable | |
| forky, sid | 7.4.21+dfsg-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| symfony | source | (unstable) | 7.4.21+dfsg-1 |
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
https://github.com/symfony/symfony/pull/65690
https://github.com/symfony/symfony/pull/66720
https://github.com/symfony/symfony/pull/66723