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CVE-2026-86349: mattermost server from 10.11.0 (inclusive), before 10.11.23 (exclusive), from 11.7.0 (inclusive), before 11.7.9…

CVE-2026-86349. CVSS 3.1 base score 4.3 (MEDIUM, Vendor/CNA). EPSS 0.00359 (percentile 0.27499), scored 2026-10-06.

Affected technology

mattermost server · from 10.11.0 (inclusive), before 10.11.23 (exclusive)
mattermost

mattermost server · from 11.7.0 (inclusive), before 11.7.9 (exclusive)
mattermost

mattermost server · from 11.8.0 (inclusive), before 11.8.5 (exclusive)
mattermost

mattermost server · from 11.9.0 (inclusive), before 11.9.1 (exclusive)
mattermost

Mattermost · 11.9.0 through 11.9.0, 11.8.0 through 11.8.4, 11.7.0 through 11.7.8, 10.11.0 through 10.11.22
Mattermost

Description’s affected range: versions 11.9.x <= 11.9.0

Component: Not specified by the source

Attack conditions (Vendor/CNA, CVSS 3.1): Network (remote) · Low privileges required · No user interaction required

What an attacker can do

An authenticated attacker can cause a denial of service (CPU resource exhaustion) via a crafted post containing deeply nested blockquotes or list items. Vendor/CNA’s CVSS 3.1 assessment (base score 4.3/10) rates confidentiality and integrity impact as none; availability impact as low.

Published

CWE
CWE-407
CCR priority
17.3 /100 (P5)
CVSS 3.1
4.3 /10 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L · Vendor/CNA
EPSS
0.00359 · percentile 0.27499 · 2026-10-06
KEV
no

Provenance

Stable permalink: https://cybercodered.org/item/cve-cve-2026-86349.html