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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-52769
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-05 00:17:19 UTC
Updated2026-09-05 00:17:19 UTC
DescriptionYesWiki 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.

Risk And Classification

Primary CVSS: v3.1 8.3 HIGH from [email protected]

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

Problem Types: CWE-918 | CWE-918 CWE-918: Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.3HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
3.1CNADECLARED8.3HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA YesWiki Yeswiki affected >= 4.6.2, < 4.6.6 Not specified

References

ReferenceSourceLinkTags
github.com/YesWiki/yeswiki/releases/tag/v4.6.6 [email protected] github.com
github.com/YesWiki/yeswiki/security/advisories/GHSA-vw42-752g-5mrp [email protected] github.com
github.com/YesWiki/yeswiki/commit/87e627f33e79879827a3669fee2aa1244612c487 [email protected] github.com
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