CVE-2026-109413
EUVD-2026-10210915.10.2026, 15:17
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.EnginsightEarly Detection
Affected products identified ahead of NVD analysis through intelligence sources.
| Vendor | Product | Version | Source |
|---|---|---|---|
| sensiolabs | symfony | 𝑥 < 5.4.54 | CNA |
| sensiolabs | symfony | 𝑥 < 6.4.45 | CNA |
| sensiolabs | symfony | 𝑥 < 7.4.18 | CNA |
| sensiolabs | symfony | 𝑥 < 8.1.6 | CNA |
Debian Releases
Common Weakness Enumeration