What is CVE-2026-24458?

CVE-2026-24458 is a high-severity vulnerability in Mattermost, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-03-16.

How severe is CVE-2026-24458?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Mattermost

CVE-2026-24458

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly handle very long passwords, which allows an attacker to overload the server CPU and memory via executing login attempts with multi-megabyte passwords. Mattermost Advisory ID: MMSA-2026-00587

EPSS: 0.003 (19.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Mattermost — versions 11.3.0, 11.2.0, 10.11.0
Mattermost Mattermost_server

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

responsibledisclosure@mattermost.com (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-24458?: CVE-2026-24458 is a high-severity vulnerability in Mattermost, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-03-16.
How severe is CVE-2026-24458?: High severity. CVSS v3 base score is 7.5 out of 10.