Existing server guests invited to the team by members without "invite_guest" permission

published 2024-02-29 2 y ago modified 2026-09-10 1 mo ago also GHSA-pfw6-5rx3-xh3c , GO-2024-2593 , EUVD-2024-0685

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 26%
public exploits: 0; none known

Mattermost fails to check the "invite_guest" permission when inviting guests of other teams to a team, allowing a member with permissions to add other members but not to add guests to add a guest to a team as long as the guest was already a guest in another team of the server

Patch / fix

fixed in 3

go github.com/mattermost/mattermost/server/v8 8.1.9, 9.2.5, 9.3.1, 9.4.2
go github.com/mattermost/mattermost-server 9.2.5+incompatible, 9.3.1+incompatible, 9.4.2+incompatible
Mattermost Mattermost 8.1.9, 9.2.5, 9.3.1, 9.4.2, 9.5.0

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-03-05)

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 26% 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	>=9.4.0, <9.4.2 >=9.3.0, <9.3.1 >=9.2.0, <9.2.5 <8.1.9 all versions	9.4.2 9.3.1 9.2.5 8.1.9
go	github.com/mattermost/mattermost-server	>=9.2.0+incompatible, <9.2.5+incompatible >=9.3.0+incompatible, <9.3.1+incompatible >=9.4.0+incompatible, <9.4.2+incompatible	9.2.5+incompatible 9.3.1+incompatible 9.4.2+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-284 Improper Access Control

References

mattermost.com /security-updates
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2024-1888
advisory
github.com /mattermost/mattermost
package
github.com /advisories/GHSA-pfw6-5rx3-xh3c
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