CVE-2026-104459: YesWiki before 4.6.7 SSRF via ActivityPub WebFinger actor_handle

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-02 · updated 2026-10-02
Weakness: CWE-918

Description

YesWiki before 4.6.7 contains a server-side request forgery vulnerability in WebfingerService that allows unauthenticated attackers to trigger HTTPS requests to internal hosts. Attackers can POST a crafted actor_handle with a numeric host and port to the abonnements view to probe internal HTTPS services and ports.

Affected products

yeswiki: before 4.6.7 — fixed in 4.6.7

How to fix

Upgrade to a fixed version: yeswiki 4.6.7. Check the vendor advisory for mitigations.

References

https://github.com/YesWiki/yeswiki/security/advisories/GHSA-x4mq-qxvc-g82j
https://www.vulncheck.com/advisories/yeswiki-before-4.6.7-ssrf-via-activitypub-webfinger-actor-handle
https://github.com/YesWiki/yeswiki/security/advisories/GHSA-x4mq-qxvc-g82j

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