CVE-2026-52769 (GCVE-0-2026-52769)

Vulnerability from cvelistv5 – Published: 2026-09-04 23:40 – Updated: 2026-09-08 13:03
VLAI
Title
YesWiki: Unauthenticated Server-Side Request Forgery via ActivityPub `Signature.keyId`
Summary
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.
Severity
8.3 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-08 13:02 UTC
CWE
  • CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7606 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
YesWiki yeswiki Affected: >= 4.6.2, < 4.6.6
guessed Create a notification for this product.
Show details on NVD website
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