Allocation of Resources Without Limits or Throttling in Mastodon - CVE-2026-23963
Published: April 23, 2026
Vulnerability identifier: #VU126993
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-23963
CWE-ID: CWE-770
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to allocation of resources without limits or throttling in list names, filter names, and filter keywords when processing user-supplied values. A remote user can set arbitrarily long names or keywords to cause a denial of service.
A user can also render their own web interface unusable, including by unknowingly approving a malicious API client.
Affected software
Mastodon
How to mitigate CVE-2026-23963
Install security update from vendor's website.
Mastodon - addressed in versions 4.3.18, 4.4.12, 4.5.5