7.5

CVE-2026-24458: DoS attack via login attempts with multi-megabyte passwords

Analyzed
AliasesGHSA-m5rv-56xx-hfc6GO-2026-4731
Published 16-03-2026Last modified 16-03-2026

Vulnerability summary

CVE-2026-24458 is a high (CVSS 7.5) vulnerability in mattermost. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 21.6% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.29%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2026:21483-1SUSE-SU-2026:1135-1

Timeline

  1. 16-03-2026
    PublishedVulnerability first disclosed.
  2. 16-03-2026
    Last modifiedVulnerability information updated.

Description

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

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.29%

Chance of exploitation in the next 30 days

Percentile

22%

Versus all other CVEs

30-day change

Increase +0.02 pp

From 0.27% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Github.com/mattermost/mattermost-server2 products
  • v5All versions (No fix recorded)
  • v6All versions (No fix recorded)
Mattermost2 products
  • mattermost11.3.0 | ≥ 11.2.0, ≤ 11.2.2 | ≥ 10.11.0, ≤ 10.11.10
  • mattermost_server≥ 10.11.0, < 10.11.11 | ≥ 11.2.0, < 11.2.3 | ≥ 11.3.0, < 11.3.1
Github.com/mattermost1 product
  • mattermost-server< 5.3.2-0.20260129164748-7201f42d955f | ≥ 10.11.0-rc1, < 10.11.11 | ≥ 11.2.0-rc1, < 11.2.3 | ≥ 11.3.0-rc1, < 11.3.1 | ≥ 11.3.0-rc1+incompatible, < 11.3.1+incompatible
Github.com/mattermost/mattermost/server1 product
  • v8< 8.0.0-20260129164748-7201f42d955f

4 vendors · 6 products

References

5 links