Improper access control in Mastodon - CVE-2026-47777
Published: May 23, 2026
Vulnerability identifier: #VU132179
CSH Severity: Medium
CVSS v4.0: 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/E:U/U:Green
CVE-ID: CVE-2026-47777
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Mastodon
Affected software:
Mastodon
Mastodon
Detailed vulnerability description
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.
How to mitigate CVE-2026-47777
Install security update from vendor's website.