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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

EPSS

• CVE-2026-52769: 0.49% estimated exploitation activity in the next 30 days; percentile 41.95 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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 (bnactivitypubenable = '1'). Details Affected component File: tools/bazar/services/HttpSignatureService.php Method: HttpSignatureService::verifySignature(Request $request) Sink: line 96 Route:…

Published by the source

9 Jul 2026, 20:58 UTC

Last modified by the source

9 Jul 2026, 20:58 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-vw42-752g-5mrp

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# Patch Next advisory brief: CVE-2026-52769

Advisory: YesWiki has Unauthenticated Server-Side Request Forgery via ActivityPub `Signature.keyId`
IDs: CVE-2026-52769, GHSA-vw42-752g-5mrp
Record: https://patchnext.com/advisories/cve-2026-52769 (revision 1, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: yeswiki/yeswiki 4.6.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist yeswiki/yeswiki: affected >= 4.6.2, < 4.6.6; fixed in 4.6.6

## Suggested inspection (read-only)
- Packagist yeswiki/yeswiki: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on yeswiki/yeswiki.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-vw42-752g-5mrp (GitHub-reviewed advisory GHSA-vw42-752g-5mrp lists affected ranges: Packagist yeswiki/yeswiki >=4.6.2 <4.6.6)

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