YesWiki: Unauthenticated Server-Side Request Forgery via ActivityPub `Signature.keyId` (CVE-2026-52769) | HOL Guard CVE

High severityCVE-2026-52769GHSA-VW42-752G-5MRP

YesWiki: Unauthenticated Server-Side Request Forgery via ActivityPub `Signature.keyId`

Answer in brief

CVE-2026-52769 records a High severity vulnerability in YesWiki: Unauthenticated Server-Side Request Forgery via ActivityPub `Signature.keyId`. The current sources do not mark it as known exploited. The current feed maps yeswiki/yeswiki (composer), YesWiki/yeswiki (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 4, 2026Updated Sep 4, 2026Source checked Sep 5, 2026First seen by HOL Jul 10, 2026Material review Sep 4, 2026

Upstream Advisory

Key facts

Risk: High
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
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 yeswiki/yeswiki (composer), YesWiki/yeswiki (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
yeswiki/yeswikicomposer	>=4.6.2,<4.6.6	4.6.6
YesWiki/yeswikigeneric	>= 4.6.2, < 4.6.6	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for yeswiki/yeswiki, YesWiki/yeswiki.
Review the reported fix. Update yeswiki/yeswiki to 4.6.6 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jul 10, 2026

Sources and claim methodology

Upstream source description

YesWiki is a wiki system written in PHP. From version 4.6.2 to before version 4.6.6, the POST /api/forms/{formId}/actor/inbox route - exposed publicly with acl:"public" - accepts an HTTP Signature header whose keyId parameter is a URL. HttpSignatureService::verifySignature() parses the header and immediately makes a server-side HTTP GET to that URL, before any cryptographic verification or URL validation. An unauthenticated remote attacker can therefore make YesWiki issue arbitrary outbound HTTP requests to any host the server can reach - internal services, cloud-metadata endpoints (169.254.169.254), intranet-only admin panels, etc. - and read enough back via timing and error-message oracles to scan ports, enumerate services, and (on a real cloud instance) reach IAM metadata. The only deployment-side precondition is that ActivityPub be enabled on at least one Bazar form. This issue has been patched in version 4.6.6.

Quoted source text, attributed separately from HOL analysis.