← CVE Intelligence

CVE-2026-109413

Symfony: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
sensiolabs / symfonyaffected 0 before v5.4.54; affected v6.0.0-BETA1 before v6.4.45; affected v7.0.0-BETA1 before v7.4.18; affected v8.0.0-BETA1 before v8.1.6

CWE

CWE-674

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.