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TI-2026-37884 Aliases CVE-2026-52769GHSA-vw42-752g-5mrp

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

Priority HIGH 75CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00487 42nd percentileScored 2026-11-07
Fix Fixed yeswiki (YesWiki): 4.6.6yeswiki/yeswiki (Packagist): 4.6.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
YesWikiyeswiki4.6.2 to before 4.6.64.6.6Patch availableCNA
—yeswiki/yeswiki (Packagist)4.6.2 to before 4.6.64.6.6Patch availableGHSA-vw42-752g-5mrp
  • yeswiki VendorYesWiki Affected 4.6.2 to before 4.6.6 Fixed in 4.6.6 Patch available CNA
  • yeswiki/yeswiki (Packagist) Vendor— Affected 4.6.2 to before 4.6.6 Fixed in 4.6.6 Patch available GHSA-vw42-752g-5mrp

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:yeswiki:yeswiki:*:*:*:*:*:*:*:*——YesWiki
  • cpe:2.3:a:yeswiki:yeswiki:*:*:*:*:*:*:*:* Versions — — ·YesWiki

Remediation

  • Fix · CNA yeswiki (YesWiki) Fixed in 4.6.6
  • Fix · GHSA-vw42-752g-5mrp yeswiki/yeswiki (Packagist) Fixed in 4.6.6 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-52769
  2. 2026-10-03 Alias added: GHSA-vw42-752g-5mrp

References

Other 4

  • TI-2026-37893 YesWiki has Unsafe eval() in Formula Calculator - Remote Code Execution (RCE) & Denial of Service (DoS) CVSS 3.1CRITICAL 9.8
  • TI-2026-34305 YesWiki: Unauthenticated SQL Injection CVSS 3.1CRITICAL 9.8
  • TI-2025-29089 YesWiki Vulnerable to Unauthenticated Site Backup Creation and Download CVSS 3.1CRITICAL 10.0
  • TI-2024-34399 Use of a Broken or Risky Cryptographic Algorithm in YesWiki CVSS 3.1CRITICAL 9.9
  • TI-2026-37882 YesWiki: Unauthenticated arbitrary page deletion via `{{erasespamedcomments}}` action CVSS 3.1CRITICAL 9.1
  • TI-2026-80227 SQL injection in YesWiki Bazar entry creation via date_maj_fiche CVSS 4.0HIGH 8.8
See all 85 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences