CVE-2026-104445: YesWiki before 4.6.7 Authentication Bypass via ActivityPub Inbox Actor Spoofing
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
YesWikito a version that resolves this vulnerability.Fixed in 4.6.7
Event History
Frequently Asked Questions
Which deployments are exposed?
YesWiki versions before 4.6.7 are affected where the ActivityPub inbox processes activities for mirrored federated entries. The vulnerable path involves activities that reference a mirrored entry's sourceUrl.
Does an attacker need a YesWiki account or a trusted federation identity?
No. An unauthenticated attacker can exploit the issue using any ActivityPub keypair to produce signed activities; the signature signer is not correctly bound to the claimed activity actor.
What can an attacker do through this issue?
An attacker can send signed Delete or Update activities to delete or overwrite other actors' federated entries, provided the activities reference a mirrored entry's sourceUrl.
What is the available remediation?
Upgrade YesWiki to version 4.6.7 or later. The issue affects versions before 4.6.7.