CVE-2026-16251CWE-770denial-of-service

CVE-2026-16251

Medium · published October 16, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
19.4
In the wild
Unconfirmed
What it is

Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to limit the size of remote image responses buffered in memory during local image proxy direct fetches, which allows a remote attacker to cause memory exhaustion on the server via a crafted oversized image response.. Mattermost Advisory ID: MMSA-2026-00726

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00280 · 19.4th percentile
Weakness
CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-10-16T12:17Z
References (1)
https://mattermost.com/security-updates · [email protected]
EPSS history
Timeline
  • 17 OCT 03:28Z
    EPSS moved — → 0%
    epss
  • 16 OCT 07:14Z
    Mattermost local image proxy allows server memory exhaustion via unbounded image response buffering
    cvelistv5
  • 16 OCT 07:14Z
    Mattermost local image proxy allows server memory exhaustion via unbounded image response buffering
    cvelistv5