CVE-2026-109449
Symfony: Unbounded Nesting in the Expression Parser Lets Untrusted Expressions Crash the Process
At a glance
- Source
- NVD
- EPSS
- EPSS 0.38 % · percentile 32 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Checkmarx
- NVD status
- Awaiting Analysis
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.
Weaknesses (CWE)
- CWE-674 — Uncontrolled Recursion
References
- 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
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | HIGH 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | Checkmarx |
| CVSS 4.0 | HIGH 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · 596c5446-0ce5-4ba2-aa66-48b3b757a647 (Secondary) |
European references
- ENISA EUVD · EUVD-2026-102134
- GCVE · GCVE-0-2026-109449
CERT-FR advisories
- CERTFR-2026-AVI-1324 — Multiples vulnérabilités dans les produits Symfony · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| sensiolabs · symfony | affected 0 < v5.4.54 ; affected v6.0.0-BETA1 < v6.4.48 ; affected v7.0.0-BETA1 < v7.4.21 ; affected v8.0.0-BETA1 < v8.1.9 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |