CVE-2026-90771
joi before 17.13.8 and 18.2.9 Prototype Pollution via messages
- State
- Published
- Severity
- 6.3 Medium
- Published
- Sep 13, 2026
- Updated
- Sep 24, 2026
- Reserved
- Sep 13, 2026
Description
joi before versions 17.13.8 and 18.2.9 contains a prototype pollution vulnerability in the messages compilation function that accepts __proto__ as an error code. Attackers can supply __proto__ keys in custom messages to replace the returned object's prototype, breaking downstream code relying on Object.prototype methods.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 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 | 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 | VulnCheck |
Weaknesses
- CWE-1321 Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Products
| Product | Versions |
|---|---|
joihapijs |
|
References
- GitHub Issue #3150issue-tracking
- https://github.com/hapijs/joiproduct
- https://github.com/hapijs/joi/blob/v18.2.8/lib/messages.jstechnical-description
- https://github.com/hapijs/joi/commit/5b8333c9177e08b4ef4ed02903c2d657084e7afbpatch
- VulnCheck Advisory: joi before 17.13.8 and 18.2.9 Prototype Pollution via messagesthird-party-advisory
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