{"id":"CVE-2026-109413","title":"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 le…","summary":"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 le…","severity":"high","cvss":8.7,"cvssVector":"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","cwe":["CWE-674"],"vendor":"sensiolabs","product":"symfony/yaml","affected":["symfony/yaml < v5.4.54","symfony/yaml >= v6.0.0-BETA1 < v6.4.45","symfony/yaml >= v7.0.0-BETA1 < v7.4.18","symfony/yaml >= v8.0.0-BETA1 < v8.1.6"],"published":"2026-10-15","updated":"2026-10-15","sourceUpdated":"2026-10-15T19:17:20.987","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-109413","references":[{"url":"https://github.com/symfony/symfony/pull/65688","label":"596c5446-0ce5-4ba2-aa66-48b3b757a647"},{"url":"https://github.com/symfony/symfony/security/advisories/GHSA-2v3c-qxhr-7vpv","label":"596c5446-0ce5-4ba2-aa66-48b3b757a647"},{"url":"https://symfony.com/blog/cve-2026-109413-unbounded-recursion-in-the-yaml-inline-lexer-lets-a-single-document-crash-the-process","label":"596c5446-0ce5-4ba2-aa66-48b3b757a647"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-15T18:06:37.552332Z"},"cvssSource":"cna","ingestedAt":"2026-10-15T15:09:08.424Z","slug":"CVE-2026-109413","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":47.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}