# CVE-2026-104445: YesWiki ActivityPub authentication bypass via actor spoofing

Source: https://junglewise.ai/threats/cve-2026-104445-yeswiki-before-4-6-7-contains-an-authentication-bypass  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-02. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-104445 · Severity: high · CVSS 8.2 · Published 2026-10-02

YesWiki is a collaborative wiki platform with ActivityPub federation support. The vulnerability allows any attacker with an ActivityPub keypair to delete or modify federated entries belonging to other users by spoofing the actor identity. An unauthenticated attacker can delete wiki entries or overwrite content from other federated actors without needing any YesWiki account.

Technologies: [YesWiki](https://junglewise.ai/threats/technologies/yeswiki). Vendors: [YesWiki](https://junglewise.ai/threats/vendors/yeswiki).

## Quick answers

**Is CVE-2026-104445 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-104445 being exploited in the wild.

**How severe is CVE-2026-104445?** High severity, with a CVSS score of 8.2, published 2 October 2026.

**Which products and versions are affected?** YesWiki before 4.6.7.

**Is there a fix for CVE-2026-104445?** Yes: fixed in 4.6.7. Until then: Disable ActivityPub federation on Bazar forms until the upgrade can be applied, or restrict network access to the ActivityPub inbox endpoint to trusted federated instances only. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-104445 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-104445?** Check whether you run YesWiki at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 4.6.7

Disable ActivityPub federation on Bazar forms until the upgrade can be applied, or restrict network access to the ActivityPub inbox endpoint to trusted federated instances only.

## Technical details

The ActivityPub inbox verifies HTTP signatures but fails to bind the verified key owner to the activity actor field, allowing actor spoofing. An attacker can send Delete or Update activities with a valid signature on their own key while claiming to be a different actor in the activity body. The vulnerable code resolves target entries only by remote object ID without checking ownership, allowing cross-actor deletion and content manipulation on any entry with a known sourceUrl.

## Affected products

- YesWiki YesWiki before 4.6.7

## Timeline

- 2026-09-01: disclosed
- 2026-10-02: advisory

## References

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

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- [YesWiki server-side request forgery in Bazar CSV import](https://junglewise.ai/threats/cve-2026-116827-yeswiki-before-4-7-0-contains-a-server-side-request-forgery)
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- [YesWiki stored cross-site scripting in referrers_sites handler](https://junglewise.ai/threats/cve-2026-116824-yeswiki-before-4-7-0-contains-a-stored-cross-site-scripting)