---
id: CVE-2026-90771
title: >-
  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
summary: >-
  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 retur…
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-1321
  - CWE-915
vendor: hapijs
product: joi
affected:
  - joi >= 16.0.0 < 17.13.8
  - joi >= 18.0.0 < 18.2.9
published: '2026-09-13'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T15:18:42.280'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90771'
references:
  - url: 'https://github.com/hapijs/joi'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/hapijs/joi/blob/v18.2.8/lib/messages.js'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/hapijs/joi/commit/5b8333c9177e08b4ef4ed02903c2d657084e7afb
    label: disclosure@vulncheck.com
  - url: 'https://github.com/hapijs/joi/issues/3150'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/joi-before-17.13.8-and-18.2.9-prototype-pollution-via-messages
    label: disclosure@vulncheck.com
  - url: 'https://github.com/hapijs/joi/issues/3150'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90771.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-90771'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532688'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-90771'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90771'
  - url: 'https://access.redhat.com/errata/RHSA-2026:67610'
  - url: 'https://access.redhat.com/errata/RHSA-2026:67573'
  - url: 'https://access.redhat.com/errata/RHSA-2026:67605'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00258
epssPercentile: 0.17794
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-16T14:02:28.580545Z'
scores:
  nvd: 3.7
  cna: 3.7
  vendor: 5.9
ingestedAt: '2026-09-14T15:23:07.471Z'
patched:
  - hardened_images
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Gatekeeper 3, Migration Toolkit for Containers, Red Hat Build of Podman Desktop, Red Hat Data Grid 8, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, … · no fix planned: Gatekeeper 3, Migration Toolkit for Containers, Red Hat Build of Podman Desktop, Red Hat Data Grid 8, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90771.json)
- **RHSA-2026:67610** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67610)
- **RHSA-2026:67573** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67573)
- **RHSA-2026:67605** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67605)