CVE-2026-4273: mattermost server from 10.11.0 (inclusive), before 10.11.14 (exclusive), from 11.5.0 (inclusive), before 11.5.2…

Affected technology

mattermost server · from 10.11.0 (inclusive), before 10.11.14 (exclusive)
mattermost

mattermost server · from 11.5.0 (inclusive), before 11.5.2 (exclusive)
mattermost

Mattermost · 11.5.0 through 11.5.1, 10.11.0 through 10.11.13
Mattermost

Description’s affected range: versions 11.5.x <= 11.5.1

Component: Not specified by the source

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

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

What an attacker can do

An authenticated attacker can bypass token rotation and reuse the original invite token via sending a crafted invite confirmation with a RefreshedToken matching the original token. Vendor/CNA’s CVSS 3.1 assessment (base score 3.7/10) rates confidentiality and availability impact as none; integrity impact as low. NVD’s CVSS 3.1 assessment (base score 4.3/10) rates confidentiality and availability impact as none; integrity impact as low.