What is CVE-2023-3581?

CVE-2023-3581 is a medium-severity vulnerability in Mattermost, classified under Origin Validation Error. CVSS score: 6.2/10. Published 2023-07-17.

How severe is CVE-2023-3581?

Medium severity. CVSS v3 base score is 6.2 out of 10.

Vulnerability in Mattermost

CVE-2023-3581

Mattermost fails to properly validate the origin of a websocket connection allowing a MITM attacker on Mattermost to access the websocket APIs.

Published 2023-07-17 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.2 (Medium). Vector: CVSS:3.1/AV:P/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (16.2th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Mattermost — versions 0, 7.8.7, 7.9.5
Mattermost Server

Weakness classification (CWE)

CWE-346 — Origin Validation Error

References

mattermost.com/security-updates (Vendor Advisory)

Frequently asked questions

What is CVE-2023-3581?: CVE-2023-3581 is a medium-severity vulnerability in Mattermost, classified under Origin Validation Error. CVSS score: 6.2/10. Published 2023-07-17.
How severe is CVE-2023-3581?: Medium severity. CVSS v3 base score is 6.2 out of 10.