What is CVE-2025-0503?

CVE-2025-0503 is a low-severity vulnerability in Mattermost, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 3.1/10. Published 2025-02-14.

How severe is CVE-2025-0503?

Low severity. CVSS v3 base score is 3.1 out of 10.

Vulnerability in Mattermost

CVE-2025-0503

Mattermost versions 9.11.x <= 9.11.6 fail to filter out DMs from the deleted channels endpoint which allows an attacker to infer user IDs and other metadata from deleted DMs if someone had manually marked DMs as deleted in the database.

Published 2025-02-14 · last modified 2026-06-17.

CVSS v3 metric

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

EPSS exploit prediction

EPSS: 0.003 (15.2th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 15.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000

Affected products

Mattermost — versions 9.11.0, 10.4.0, 9.11.7
Mattermost Server

Weakness classification (CWE)

CWE-754 — Improper Check for Unusual or Exceptional Conditions

References

mattermost.com/security-updates (Vendor Advisory)

Frequently asked questions

What is CVE-2025-0503?: CVE-2025-0503 is a low-severity vulnerability in Mattermost, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 3.1/10. Published 2025-02-14.
How severe is CVE-2025-0503?: Low severity. CVSS v3 base score is 3.1 out of 10.