What is CVE-2026-75588?

CVE-2026-75588 is a low-severity vulnerability in Mattermost, classified under CWE-1287. CVSS score: 2.6/10. Published 2026-09-17.

How severe is CVE-2026-75588?

Low severity. CVSS v3 base score is 2.6 out of 10.

Vulnerability in Mattermost

CVE-2026-75588

Mattermost Desktop App versions <=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717

CVSS v3 metric

CVSS v3 base score 2.6 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N.

Affected products

Mattermost

Weakness classification (CWE)

CWE-1287

References

responsibledisclosure@mattermost.com (vendor-advisory)

Frequently asked questions

What is CVE-2026-75588?: CVE-2026-75588 is a low-severity vulnerability in Mattermost, classified under CWE-1287. CVSS score: 2.6/10. Published 2026-09-17.
How severe is CVE-2026-75588?: Low severity. CVSS v3 base score is 2.6 out of 10.