YesWiki has Unauthenticated Server-Side Request Forgery via ActivityPub `Signature.keyId`
Published Sep 4, 2026 · Updated Oct 23, 2026 · Also known as GHSA-vw42-752g-5mrp
Original summary
Normalized public record · Updated Oct 23, 2026
YesWiki has Unauthenticated Server-Side Request Forgery via ActivityPub `Signature.keyId`
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
## 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.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- 10%
- Aliases
- GHSA-vw42-752g-5mrp
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
Record history
Published Sep 4, 2026 · Last refreshed Oct 23, 2026