joi before 17.13.8 and 18.2.9 Prototype Pollution via messages (CVE-2026-90771) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-90771

joi before 17.13.8 and 18.2.9 Prototype Pollution via messages

Answer in brief

CVE-2026-90771 records a Unknown severity vulnerability in joi before 17.13.8 and 18.2.9 Prototype Pollution via messages. The current sources do not mark it as known exploited. The current feed maps hapijs/joi (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 13, 2026Updated Sep 13, 2026Source checked Sep 14, 2026First seen by HOL Sep 13, 2026Material review Sep 13, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps hapijs/joi (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
hapijs/joigeneric	>=16.0.0 <17.13.8 \|\| >=18.0.0 <18.2.9	17.13.8, 18.2.9

Recommended response

Check inventory. Check lockfiles and deployed manifests for hapijs/joi.
Review the reported fix. Update hapijs/joi to 17.13.8 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 13, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.