CVE-2026-45133Symfony: [Yaml] Harden the parser when handling untrusted input
- 8.2HighCVSS base score
- 0.63%Exploitation in 30 daysEPSS · top 49% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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, 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.
Timeline
ID reserved
By GitHub_M
- 2 months later
· 2 months later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | High8.2 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| NVDNVD · Analyzed | 4.0 | High8.2 | CVSS:4.0/AV:N/AC:L/AT:P/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.63% · top 49% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.2.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Packagistsymfony/symfonyGHSA-c2p3-7m5p-cv8x (opens in a new tab)
- Packagistsymfony/yamlGHSA-c2p3-7m5p-cv8x (opens in a new tab)
References
References5
- https://github.com/symfony/symfony/security/advisories/GHSA-c2p3-7m5p-cv8x (opens in a new tab)x_refsource_CONFIRM
- https://github.com/symfony/symfony/releases/tag/v5.4.52 (opens in a new tab)x_refsource_MISC
- https://github.com/symfony/symfony/releases/tag/v6.4.40 (opens in a new tab)x_refsource_MISC
- https://github.com/symfony/symfony/releases/tag/v7.4.12 (opens in a new tab)x_refsource_MISC
- https://github.com/symfony/symfony/releases/tag/v8.0.12 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-44351 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-c2p3-7m5p-cv8x (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-45133)Record last updated .