{"id":"CVE-2026-109449","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-109449","generatedAt":"2026-10-28T04:17:58.248Z","title":"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…","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.","published":"2026-10-15T16:17:44.000Z","lastModified":"2026-10-16T16:00:34.000Z","status":"Awaiting Analysis","sourceIdentifier":"596c5446-0ce5-4ba2-aa66-48b3b757a647","cvss":{"version":"4.0","score":8.7,"severity":"HIGH","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-674"],"affected":[],"epss":{"score":0.00378,"percentile":0.31568,"date":"2026-10-27","history":[{"date":"2026-10-16","score":0.00524,"percentile":0.43136}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.38%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-15T16:17:44.000Z","detail":{"score":"8.7","severity":"HIGH","publishedAt":"2026-10-15T16:17:43.963Z"},"summary":"New CVE, high severity (CVSS 8.7)."}],"references":[{"url":"https://github.com/symfony/symfony/pull/65690","source":"596c5446-0ce5-4ba2-aa66-48b3b757a647"},{"url":"https://github.com/symfony/symfony/pull/66720","source":"596c5446-0ce5-4ba2-aa66-48b3b757a647"},{"url":"https://github.com/symfony/symfony/pull/66723","source":"596c5446-0ce5-4ba2-aa66-48b3b757a647"},{"url":"https://github.com/symfony/symfony/security/advisories/GHSA-7rpj-w9pf-39rr","source":"596c5446-0ce5-4ba2-aa66-48b3b757a647"},{"url":"https://symfony.com/blog/cve-2026-109449-unbounded-nesting-in-the-expression-parser-lets-untrusted-expressions-crash-the-process","source":"596c5446-0ce5-4ba2-aa66-48b3b757a647"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-109449","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}