What is CVE-2023-1776?

CVE-2023-1776 is a high-severity vulnerability in Mattermost, classified under Cross-site Scripting. CVSS score: 7.3/10. Published 2023-03-31.

How severe is CVE-2023-1776?

High severity. CVSS v3 base score is 7.3 out of 10.

XSS in Mattermost

CVE-2023-1776

Boards in Mattermost allows an attacker to upload a malicious SVG image file as an attachment to a card and share it using a direct link to the file.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2023-03-31 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.004 (36.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Mattermost — versions 3.3.0, 7.8.0, 7.7.2
Mattermost Server — versions 7.7.1

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

mattermost.com/security-updates/ (Vendor Advisory)

Frequently asked questions

What is CVE-2023-1776?: CVE-2023-1776 is a high-severity vulnerability in Mattermost, classified under Cross-site Scripting. CVSS score: 7.3/10. Published 2023-03-31.
How severe is CVE-2023-1776?: High severity. CVSS v3 base score is 7.3 out of 10.