Improper access control in Mastodon - CVE-2026-47777
Published: May 23, 2026
Vulnerability identifier: #VU132179
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-47777
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass consent checks and falsify authorization for inclusion in a remote collection.
The vulnerability exists due to improper access control in the remote Collections consent verification logic when processing a forged FeatureAuthorization object. A remote attacker can forge a FeatureAuthorization object to bypass consent checks and falsify authorization for inclusion in a remote collection.
Only instances with the experimental "Collections" feature enabled are vulnerable.
Affected software
Mastodon
How to mitigate CVE-2026-47777
Install security update from vendor's website.
Mastodon - addressed in versions 4.3.23, 4.4.17, 4.5.10