CVE-2026-45304
Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Yaml\Parser resolved YAML collection aliases recursively, allowing a small untrusted YAML input to expand into a multi-gigabyte structure and exhaust memory.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.68%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Symfony 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, Symfony\Component\Yaml\Parser resolved YAML collection aliases recursively, allowing a small untrusted YAML input to expand into a multi-gigabyte structure and exhaust memory. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
- CVSS 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.68% probability · 51th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-776
- Affected
- sensiolabs/symfony
- Source
- security-advisories@github.com
References
- https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970aPatch
- https://github.com/symfony/symfony/releases/tag/v5.4.52Product, Release Notes
- https://github.com/symfony/symfony/releases/tag/v6.4.40Product, Release Notes
- https://github.com/symfony/symfony/releases/tag/v7.4.12Product, Release Notes
- https://github.com/symfony/symfony/releases/tag/v8.0.12Product, Release Notes
- https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4Patch, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.