{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-109413", "assignerOrgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647", "state": "PUBLISHED", "assignerShortName": "Checkmarx", "dateReserved": "2026-10-12T15:28:55.069Z", "datePublished": "2026-10-15T14:57:00.211Z", "dateUpdated": "2026-10-15T18:06:55.183Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647", "shortName": "Checkmarx", "dateUpdated": "2026-10-15T15:29:00.531Z" }, "title": "Symfony: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process", "problemTypes": [ { "descriptions": [ { "lang": "en", "cweId": "CWE-674", "description": "CWE-674 Uncontrolled Recursion", "type": "CWE" } ] } ], "affected": [ { "vendor": "sensiolabs", "product": "symfony", "collectionURL": "https://packagist.org/packages/symfony/yaml", "packageName": "symfony/yaml", "repo": "https://github.com/symfony/yaml", "modules": [ "Symfony\\\\Component\\\\Yaml\\\\Parser::lexInlineStructure()" ], "versions": [ { "status": "affected", "version": "0", "lessThan": "v5.4.54", "versionType": "git" }, { "status": "affected", "version": "v6.0.0-BETA1", "lessThan": "v6.4.45", "versionType": "git" }, { "status": "affected", "version": "v7.0.0-BETA1", "lessThan": "v7.4.18", "versionType": "git" }, { "status": "affected", "version": "v8.0.0-BETA1", "lessThan": "v8.1.6", "versionType": "git" } ], "defaultStatus": "unaffected" } ], "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" } ] } ] } ], "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.", "supportingMedia": [ { "type": "text/html", "base64": false, "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.

Any 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.

This 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.

" } ] } ], "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" } } ], "credits": [ { "lang": "en", "value": "Nicolas Grekas", "type": "remediation developer" } ], "source": { "discovery": "UNKNOWN" }, "x_generator": { "engine": "Vulnogram 1.0.5" } }, "adp": [ { "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" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T18:06:55.183Z" } } ] } }