Members Without Guest Invite Permissions Can Add Guests to Teams

published 2025-05-15 17 mo ago modified 2026-06-17 4 mo ago also GHSA-r7r2-m3vr-c8qc , GO-2025-3693 , EUVD-2025-15149

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits: 0; none known

Mattermost versions 10.6.x <= 10.6.1, 10.5.x <= 10.5.2, 10.4.x <= 10.4.4, 9.11.x <= 9.11.11 fail to check the correct permissions which allows authenticated users who only have permission to invite non-guest users to a team to add guest users to that team via the API to add a single user to a team.

Patch / fix

fixed in 3 distros 1

go github.com/mattermost/mattermost/server/v8 8.0.0-20250415054241-76ab3867b785, 9.11.12, 10.4.5, 10.5.3, 10.6.2
go github.com/mattermost/mattermost-server 9.11.12+incompatible, 10.4.5+incompatible, 10.5.3+incompatible, 10.6.2+incompatible
Mattermost Mattermost 9.11.12, 10.4.5, 10.5.3, 10.6.2, 10.7.0

govulncheck-vulndb openSUSE Tumbleweed 0.0.20250523T151856-1.1

opensuse advisories openSUSE-SU-2025:15159-1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 17 mo ago (2025-05-15)

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 17% 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
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	>=10.6.0, <10.6.2 >=10.5.0, <10.5.3 >=10.4.0, <10.4.5 >=9.11.0, <9.11.12 <8.0.0-20250415054241-76ab3867b785	10.6.2 10.5.3 10.4.5 9.11.12 8.0.0-20250415054241-76ab3867b785
go	github.com/mattermost/mattermost-server	>=9.11.0+incompatible, <9.11.12+incompatible >=10.4.0+incompatible, <10.4.5+incompatible >=10.5.0+incompatible, <10.5.3+incompatible >=10.6.0+incompatible, <10.6.2+incompatible	9.11.12+incompatible 10.4.5+incompatible 10.5.3+incompatible 10.6.2+incompatible
go	github.com/mattermost/mattermost-server/v5	all versions	no fix listed
go	github.com/mattermost/mattermost-server/v6	all versions	no fix listed

Affected products

Mattermost Mattermost

Classification

Weakness

CWE-863 Incorrect Authorization

References

mattermost.com /security-updates
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2025-3446
advisory
github.com /mattermost/mattermost
package
github.com /advisories/GHSA-r7r2-m3vr-c8qc
advisory

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