{"cve":"CVE-2026-109449","nvd":{"published":"2026-10-15T16:17:43.963","modified":"2026-10-16T16:00:33.533","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.\n\n\n#[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.\n\nThis 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.","cvss_v4":{"vector":"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","score":8.7},"cvss_v3":null,"cwes":["CWE-674"],"references":["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"],"products":[],"source":"nvd","synced_at":"2026-10-19T23:00:53.604569364+00:00"},"epss":{"cve":"CVE-2026-109449","score":0.00378,"percentile":0.315,"date":"2026-10-26"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}