What is CVE-2022-3257?

CVE-2022-3257 is a low-severity vulnerability in Mattermost, classified under Uncontrolled Resource Consumption. CVSS score: 3.1/10. Published 2022-09-23.

How severe is CVE-2022-3257?

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

Arbitrary file upload in Mattermost

CVE-2022-3257

Mattermost version 7.1.x and earlier fails to sufficiently process a specifically crafted GIF file when it is uploaded while drafting a post, which allows authenticated users to cause resource exhaustion while processing the file, resulting in server-side Denial of Service.

Vulnerability class: DoS (Denial of Service)

Published 2022-09-23 · 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:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.013 (68.4th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 68.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.013 · change: +0.001

Affected products

Mattermost — versions unspecified
Mattermost Server

Weakness classification (CWE)

References

mattermost.com/security-updates/ (Vendor Advisory)
hackerone.com/reports/1620170 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2022-3257?: CVE-2022-3257 is a low-severity vulnerability in Mattermost, classified under Uncontrolled Resource Consumption. CVSS score: 3.1/10. Published 2022-09-23.
How severe is CVE-2022-3257?: Low severity. CVSS v3 base score is 3.1 out of 10.