CVE-2026-122131
Joi 17.13.6 before 17.13.9 and 18.2.5 before 18.3.1 Prototype Replacement via __proto__ Language Key
Joi 17.13.6 before 17.13.9 and 18.2.5 before 18.3.1 contains a prototype pollution vulnerability in lib/messages.js compile() and merge() that fails to reject a __proto__ language key. Attackers supplying untrusted message configuration via any().messages(), prefs, validate options or Joi.extend can replace the compiled messages prototype, altering or breaking validation error rendering and dependent logic.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| joi hapijs joi
npm |
≥ 17.13.6; < 17.13.9 (affected, semver) ≥ 18.2.5; < 18.3.1 (affected, semver) Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 6.3 medium |
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 3.7 low |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N | CNA: VulnCheck |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/hapijs/joi/commit/76f5771e1afe527cfda24be0e1a920ffa54888d6CNA: VulnCheck · patch
- https://github.com/hapijs/joiCNA: VulnCheck · product
- https://github.com/hapijs/joi/commit/dae9467cec27e787bfdea8b276595177d52d28ecCNA: VulnCheck · patch
- https://github.com/hapijs/joi/pull/3164CNA: VulnCheck · patch, issue-tracking
- https://github.com/hapijs/joi/security/advisories/GHSA-6w3j-5fw6-r9vrCNA: VulnCheck · related, vendor-advisory
- https://github.com/hapijs/joi/blob/v18.3.0/lib/messages.js#L64-L67CNA: VulnCheck · technical-description
- https://www.vulncheck.com/advisories/joi-17.13.6-before-17.13.9-and-18.2.5-before-18.3.1-prototype-replacement-via-proto-language-keyCNA: VulnCheck · third-party-advisory
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