Username and Icon override can be used by members when Hardened Mode is enabled

published 2023-11-27 2 y ago modified 2026-09-10 1 mo ago also GHSA-jj46-9cgh-qmfx , EUVD-2023-2989

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits: 0; none known

Mattermost fails to check if hardened mode is enabled when overriding the username and/or the icon when posting a post. If settings allowed integrations to override the username and profile picture when posting, a member could also override the username and icon when making a post even if the Hardened Mode setting was enabled

Patch / fix

fixed in 3

go github.com/mattermost/mattermost/server/v8 8.1.4
go github.com/mattermost/mattermost-server/v6 7.8.13
Mattermost Mattermost 7.8.13, 8.1.4

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
NVD	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
GitHub	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
go	github.com/mattermost/mattermost/server/v8	<8.1.4	8.1.4
go	github.com/mattermost/mattermost-server/v6	<7.8.13	7.8.13

Affected products

Mattermost Mattermost

Classification

Weakness

CWE-284 Improper Access Control

References

mattermost.com /security-updates
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2023-47865
advisory
github.com /mattermost/mattermost
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary