{"id":"CVE-2026-109413","state":"PUBLISHED","title":"Symfony: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process","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.","publishedAt":"2026-10-15T14:57:00.211Z","updatedAt":"2026-10-15T18:06:55.183Z","severity":{"score":8.7,"label":"High","version":"4.0","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","source":"Checkmarx"},"assigner":"Checkmarx","products":["sensiolabs symfony"],"affected":[{"vendor":"sensiolabs","product":"symfony","packageName":"symfony/yaml","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"v5.4.54","versionType":"git"},{"version":"v6.0.0-BETA1","status":"affected","lessThan":"v6.4.45","versionType":"git"},{"version":"v7.0.0-BETA1","status":"affected","lessThan":"v7.4.18","versionType":"git"},{"version":"v8.0.0-BETA1","status":"affected","lessThan":"v8.1.6","versionType":"git"}],"collectionURL":"https://packagist.org/packages/symfony/yaml","repo":"https://github.com/symfony/yaml","modules":["Symfony\\\\Component\\\\Yaml\\\\Parser::lexInlineStructure()"]}],"references":["https://github.com/symfony/symfony/security/advisories/GHSA-2v3c-qxhr-7vpv","https://symfony.com/blog/cve-2026-109413-unbounded-recursion-in-the-yaml-inline-lexer-lets-a-single-document-crash-the-process","https://github.com/symfony/symfony/pull/65688"],"weaknesses":["CWE-674"],"ingestedAt":"2026-10-29T20:10:33.477Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/109xxx/CVE-2026-109413.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-109413","state":"PUBLISHED","datePublished":"2026-10-15T14:57:00.211Z","dateUpdated":"2026-10-15T18:06:55.183Z","assignerShortName":"Checkmarx","assignerOrgId":"596c5446-0ce5-4ba2-aa66-48b3b757a647","dateReserved":"2026-10-12T15:28:55.069Z"},"containers":{"cna":{"title":"Symfony: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"sensiolabs","product":"symfony","packageName":"symfony/yaml","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"v5.4.54","versionType":"git"},{"version":"v6.0.0-BETA1","status":"affected","lessThan":"v6.4.45","versionType":"git"},{"version":"v7.0.0-BETA1","status":"affected","lessThan":"v7.4.18","versionType":"git"},{"version":"v8.0.0-BETA1","status":"affected","lessThan":"v8.1.6","versionType":"git"}],"collectionURL":"https://packagist.org/packages/symfony/yaml","repo":"https://github.com/symfony/yaml","modules":["Symfony\\\\Component\\\\Yaml\\\\Parser::lexInlineStructure()"]}],"references":[{"url":"https://github.com/symfony/symfony/security/advisories/GHSA-2v3c-qxhr-7vpv","tags":["third-party-advisory"]},{"url":"https://symfony.com/blog/cve-2026-109413-unbounded-recursion-in-the-yaml-inline-lexer-lets-a-single-document-crash-the-process","tags":["vendor-advisory"]},{"url":"https://github.com/symfony/symfony/pull/65688","tags":["patch"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":8.7,"vectorString":"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-674","lang":"en","description":"CWE-674 Uncontrolled Recursion","type":"CWE"}]}],"providerMetadata":{"shortName":"Checkmarx","orgId":"596c5446-0ce5-4ba2-aa66-48b3b757a647","dateUpdated":"2026-10-15T15:29:00.531Z"},"cpeApplicability":[{"operator":"OR","nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*","versionStartIncluding":"0","versionEndExcluding":"v5.4.54"},{"vulnerable":true,"criteria":"cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*","versionStartIncluding":"v6.0.0-beta1","versionEndExcluding":"v6.4.45"},{"vulnerable":true,"criteria":"cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*","versionStartIncluding":"v7.0.0-beta1","versionEndExcluding":"v7.4.18"},{"vulnerable":true,"criteria":"cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*","versionStartIncluding":"v8.0.0-beta1","versionEndExcluding":"v8.1.6"}]}]}],"credits":[{"lang":"en","value":"Nicolas Grekas","type":"remediation developer"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.5"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-15T18:06:37.552332Z","id":"CVE-2026-109413","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T18:06:55.183Z"}}]}}}