CVE-2026-52769High· 8.3▾ MidnightPoC availableYesWiki 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. H…
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 45.7 · likelihood 0.1 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Sep 5.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.3%
Last analysed / modified upstream
Exploit / PoC code exists
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.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
yeswiki/yeswiki >= 4.6.2, < 4.6.6Patched in:
yeswiki/yeswiki 4.6.6Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-52762High· 7.1YesWiki is a wiki system written in PHP
CVE-2026-52766Critical· 9.1YesWiki is a wiki system written in PHP
CVE-2026-52767High· 8.2YesWiki is a wiki system written in PHP
CVE-2026-52770High· 7.5YesWiki is a wiki system written in PHP
CVE-2026-52772Medium· 5.5YesWiki is a wiki system written in PHP
CVE-2026-52773Medium· 6.1YesWiki is a wiki system written in PHP