YesWiki up to 4.6.5 HttpSignatureService inbox verifySignature keyId server-side request forgery

Summaryinfo

A vulnerability classified as problematic was found in YesWiki up to 4.6.5. The affected element is the function HttpSignatureService::verifySignature of the file /api/forms/{formId}/actor/inbox of the component HttpSignatureService. Executing a manipulation of the argument keyId can lead to server-side request forgery. This vulnerability is handled as CVE-2026-52769. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as problematic was found in YesWiki up to 4.6.5. This vulnerability affects the function HttpSignatureService::verifySignature of the file /api/forms/{formId}/actor/inbox of the component HttpSignatureService. The manipulation of the argument keyId with an unknown input leads to a server-side request forgery vulnerability. The CWE definition for the vulnerability is CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. As an impact it is known to affect confidentiality. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-52769 since 06/08/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

Upgrading to version 4.6.6 eliminates this vulnerability.

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Productinfo

Type

• Content Management System

Name

• YesWiki

Version

• 4.6.0
• 4.6.1
• 4.6.2
• 4.6.3
• 4.6.4
• 4.6.5

Website

• Product: https://github.com/YesWiki/yeswiki/

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