CVE-2026-45133

NameCVE-2026-45133
DescriptionSymfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, when the parser is exposed to attacker-controlled input, deeply nested mappings or sequences cause both the block-level (Parser::parseBlock()) and inline (Inline::parseSequence() / Inline::parseMapping()) parsers to recurse without a depth limit. A crafted document exhausts the PHP stack and crashes the worker. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-6312-1, DSA-6317-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
symfony (PTS)bullseye4.4.19+dfsg-2+deb11u6vulnerable
bullseye (security)4.4.19+dfsg-2+deb11u7vulnerable
bookworm, bookworm (security)5.4.53+dfsg-0+deb12u1fixed
trixie (security), trixie6.4.41+dfsg-0+deb13u1fixed
forky, sid7.4.14+dfsg-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
symfonysourcebookworm5.4.53+dfsg-0+deb12u1DSA-6317-1
symfonysourcetrixie6.4.41+dfsg-0+deb13u1DSA-6312-1
symfonysource(unstable)7.4.12+dfsg-1

Notes

https://symfony.com/blog/cve-2026-45133-yaml-parser-stack-exhaustion-via-unbounded-recursion-in-nested-blocks-sequences-and-mappings

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