CVE-2026-5163

CVSS Score & Metrics

Base Score

6.5 / 10

Vector String

                                        CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N                                    

Vulnerability Description

Mattermost versions 11.5.x <= 11.5.1 fail to verify channel membership when processing AI-assisted message rewrites which allows an authenticated attacker to read the content of threads in private channels and direct messages they do not have access to via a crafted request to the post rewrite endpoint.. Mattermost Advisory ID: MMSA-2026-00645

Vulnerability Details

Published Date

May 18, 2026

Last Modified

May 18, 2026

CWE ID

CWE-862

Source

NVD

Vendor

mattermost

Product

mattermost_server

External References

https://mattermost.com/security-updates

CVSS Score & Metrics

Vulnerability Description

Vulnerability Details

External References

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