{"schemaVersion":3,"id":"CVE-2026-109413","aliases":["UBUNTU-CVE-2026-109413","DEBIAN-CVE-2026-109413"],"status":"published","duplicateOf":null,"title":null,"description":"In Symfony YAML prior to versions 5.4.54, 6.4.45, 7.4.18, and 8.1.6, Yaml\\Parser::lexInlineStructure() recursed through lexInlineMapping() and lexInlineSequence() for every { and [ of an inline collection, without entering the nesting level that the rest of the parser bounds with maxNestingLevel. A document made of deeply nested inline collections, such as [[[[...]]]], exhausted the stack while it was being lexed: depending on the PHP version and its stack settings, the process crashed or the request ended with a fatal error.\n\n\n\nAny code parsing untrusted YAML is affected. That includes #[MapRequestPayload] when the Yaml component is installed and the endpoint does not restrict acceptFormat: a single unauthenticated request with a YAML content type is enough.\n\n\n\nThis issue affects symfony/yaml through v5.4.53, v6.0.0-BETA1 through v6.4.44, v7.0.0-BETA1 through v7.4.17, and v8.0.0-BETA1 through v8.1.5.","dates":{"published":"2026-10-15T14:57:00.211Z","modified":"2026-10-15T18:06:55.183Z","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":0.00507,"percentile":0.41995,"severity":"low","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[{"date":"2026-10-16T00:00:00.000Z","score":0.00507,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00507,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00507,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00507,"percentile":0.41995}],"last30":[{"date":"2026-10-16T00:00:00.000Z","score":0.00507,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00507,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00507,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00507,"percentile":0.41995}]},"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":"< 7.4.18+dfsg-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 7.4.18+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, < v6.4.45","noFixRecorded":false,"fixedIn":null},{"text":"≥ v7.0.0-BETA1, < v7.4.18","noFixRecorded":false,"fixedIn":null},{"text":"≥ v8.0.0-BETA1, < v8.1.6","noFixRecorded":false,"fixedIn":null}],"versionsText":"< v5.4.54 | ≥ v6.0.0-BETA1, < v6.4.45 | ≥ v7.0.0-BETA1, < v7.4.18 | ≥ v8.0.0-BETA1, < v8.1.6","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-2v3c-qxhr-7vpv","label":"github.com/symfony/symfony/security/advisories/GHSA-2v3c-qxhr-7vpv","hostname":"github.com","tags":["Third Party Advisory","REPORT"]},{"url":"https://symfony.com/blog/cve-2026-109413-unbounded-recursion-in-the-yaml-inline-lexer-lets-a-single-document-crash-the-process","label":"symfony.com/blog/…","hostname":"symfony.com","tags":["Vendor Advisory","REPORT"]},{"url":"https://github.com/symfony/symfony/pull/65688","label":"github.com/symfony/symfony/pull/65688","hostname":"github.com","tags":["Patch","REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-109413","label":"ubuntu.com/security/CVE-2026-109413","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-109413","label":"www.cve.org/CVERecord?id=CVE-2026-109413","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-109413","label":"security-tracker.debian.org/tracker/CVE-2026-109413","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-10-15T14:57:00.211Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-10-15T18:06:55.183Z","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":"2026-10-20T01:15:38.309Z","stale":false,"partial":false}}