CVE-2026-109413
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 lexInlineSequenc…
Impact
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 packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | symfony/symfony | >= 2.0.0, < 5.4.54 | 5.4.54 |
| composer | symfony/yaml | >= 2.0.0, < 5.4.54 | 5.4.54 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-2v3c-qxhr-7vpv
- https://github.com/symfony/symfony/security/advisories/GHSA-2v3c-qxhr-7vpv
- https://nvd.nist.gov/vuln/detail/CVE-2026-109413
- https://github.com/symfony/symfony/pull/65688
- https://github.com/symfony/symfony/commit/116287c3b5bc057e7a0420d2e52d384e14ea9417
- https://github.com/symfony/symfony/commit/2a8bf9c58d862b0c76a35ce288d1ba6a27223aad
- https://github.com/symfony/symfony/commit/8fb436fed9658a79d220e9f2b1ba8a2095559018
- https://github.com/symfony/symfony/commit/ab61e6cfd35042f16840a00f485eab2481dd4c2a
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-109413.yaml
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/yaml/CVE-2026-109413.yaml
- https://github.com/symfony/symfony/releases/tag/v5.4.54
- https://github.com/symfony/symfony/releases/tag/v6.4.45
- https://github.com/symfony/symfony/releases/tag/v7.4.18
- https://github.com/symfony/symfony/releases/tag/v8.1.6
- https://symfony.com/blog/cve-2026-109413-unbounded-recursion-in-the-yaml-inline-lexer-lets-a-single-document-crash-the-process
- https://symfony.com/cve-2026-109413