Input validation error in Mastodon - CVE-2026-23962
Published: April 23, 2026
Vulnerability identifier: #VU126992
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-23962
CWE-ID: CWE-20
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 cause a denial of service.
The vulnerability exists due to improper input validation in poll handling for remote posts when processing remote posts containing an excessive number of poll options. A remote attacker can create a remote post with a very large number of poll options to cause a denial of service.
The issue can cause disproportionate resource consumption in both Mastodon servers and clients.
How to mitigate CVE-2026-23962
Install security update from vendor's website.