{"schemaVersion":3,"id":"CVE-2026-109449","aliases":["UBUNTU-CVE-2026-109449","DEBIAN-CVE-2026-109449"],"status":"published","duplicateOf":null,"title":null,"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.","dates":{"published":"2026-10-15T15:19:08.663Z","modified":"2026-10-15T18:05:32.422Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":8.7,"severity":"high","version":"4.0","versionLabel":"v4.0","source":"CVE.org","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","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","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","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"NVD","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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"OSV · Ubuntu","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","exploitability":null,"impact":null,"computed":true},{"version":"4.0","versionLabel":"v4.0","source":"OSV · Debian","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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","exploitability":null,"impact":null,"computed":true}]},"epss":{"probability":0.00524,"percentile":0.43282,"severity":"low","asOf":"2026-10-20T00:00:00.000Z","change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[{"date":"2026-10-16T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00524,"percentile":0.43282}],"last30":[{"date":"2026-10-16T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00524,"percentile":0.43282}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-674","name":"Uncontrolled Recursion","description":"The product does not properly control the amount of recursion that takes place,  consuming excessive resources, such as allocated memory or the program stack.","type":"weakness","status":"Draft","abstraction":"Class","likelihoodOfExploit":null,"url":"https://cwe.mitre.org/data/definitions/674.html"}],"affected":[{"vendor":"debian","product":"symfony","name":"symfony","label":"symfony","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/symfony","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null},{"text":"< 7.4.21+dfsg-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 7.4.21+dfsg-1","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"symfony","name":"symfony","label":"symfony","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/symfony","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"sensiolabs","product":"symfony","name":"symfony","label":"symfony","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< v5.4.54","noFixRecorded":false,"fixedIn":null},{"text":"≥ v6.0.0-BETA1, < v6.4.48","noFixRecorded":false,"fixedIn":null},{"text":"≥ v7.0.0-BETA1, < v7.4.21","noFixRecorded":false,"fixedIn":null},{"text":"≥ v8.0.0-BETA1, < v8.1.9","noFixRecorded":false,"fixedIn":null}],"versionsText":"< v5.4.54 | ≥ v6.0.0-BETA1, < v6.4.48 | ≥ v7.0.0-BETA1, < v7.4.21 | ≥ v8.0.0-BETA1, < v8.1.9","eol":{"isEol":null,"eolDate":null,"matchMethod":"cpe","cycle":null,"product":{"name":"symfony","label":"Symfony","category":"framework"}},"hubHref":"/vendor/sensiolabs/symfony"}],"affectedCount":3,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/symfony/symfony/security/advisories/GHSA-7rpj-w9pf-39rr","label":"github.com/symfony/symfony/security/advisories/GHSA-7rpj-w9pf-39rr","hostname":"github.com","tags":["Third Party Advisory","REPORT"]},{"url":"https://symfony.com/blog/cve-2026-109449-unbounded-nesting-in-the-expression-parser-lets-untrusted-expressions-crash-the-process","label":"symfony.com/blog/…","hostname":"symfony.com","tags":["Vendor Advisory","REPORT"]},{"url":"https://github.com/symfony/symfony/pull/65690","label":"github.com/symfony/symfony/pull/65690","hostname":"github.com","tags":["Patch","REPORT"]},{"url":"https://github.com/symfony/symfony/pull/66720","label":"github.com/symfony/symfony/pull/66720","hostname":"github.com","tags":["Patch","REPORT"]},{"url":"https://github.com/symfony/symfony/pull/66723","label":"github.com/symfony/symfony/pull/66723","hostname":"github.com","tags":["Patch","REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-109449","label":"ubuntu.com/security/CVE-2026-109449","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-109449","label":"www.cve.org/CVERecord?id=CVE-2026-109449","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-109449","label":"security-tracker.debian.org/tracker/CVE-2026-109449","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-10-15T15:19:08.663Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-10-15T18:05:32.422Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":35,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T21:22:24.314Z","stale":false,"partial":false}}