CVE-2026-3115 json
Guest users can view group member IDs without respecting view restrictions
published 7mo ago modified 4mo ago also GHSA-mpc7-mm28-f6wq , GO-2026-5512 , EUVD-2026-16245
- cvss
- 4.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 15%
- public exploits
- 0
- none known
Summary
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594
Patch / fix
- go github.com/mattermost/mattermost/server/v8 8.0.0-20260217110922-b7d4a1f1f59b, 10.11.11, 11.2.3, 11.3.2, 11.4.1
- go github.com/mattermost/mattermost-server 10.11.11+incompatible, 11.2.3+incompatible, 11.3.2+incompatible, 11.4.1+incompatible
- Mattermost Mattermost 10.11.11, 11.2.3, 11.3.2, 11.4.1, 11.5.0
- govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
opensuse advisories openSUSE-SU-2026:21483-1
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red hat product security vex CVE-2026-3115 updated cvss 4.3
mattermost: Mattermost: Information disclosure via group retrieval endpoint
-
Red Hat All currently supported Red Hat productsnot affected: vulnerable code not present
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 7mo ago
Exploit prediction
0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-09).
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:L/I:N/A:N |
| GitHub | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/mattermost/mattermost/server/v8 | >=11.4.0, <11.4.1 >=11.3.0-rc1, <11.3.2 >=11.2.0-rc1, <11.2.3 >=10.11.0-rc1, <10.11.11 >=8.0.0-20260105080200-d27a2195068d, <8.0.0-20260217110922-b7d4a1f1f59b |
11.4.1 11.3.2 11.2.3 10.11.11 8.0.0-20260217110922-b7d4a1f1f59b |
| go | github.com/mattermost/mattermost-server | >=10.11.0-rc1+incompatible, <10.11.11+incompatible >=11.2.0-rc1+incompatible, <11.2.3+incompatible >=11.3.0-rc1+incompatible, <11.3.2+incompatible >=11.4.0+incompatible, <11.4.1+incompatible |
10.11.11+incompatible 11.2.3+incompatible 11.3.2+incompatible 11.4.1+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
vendor-advisory, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-3115
advisory
-
github.com
/mattermost/mattermost
package
-
github.com
/advisories/GHSA-mpc7-mm28-f6wq
advisory
Sources
- CVE List CVE-2026-3115
- GitHub Advisory GHSA-mpc7-mm28-f6wq
- NVD CVE-2026-3115
- OSV GO-2026-5512
Fencer Intel 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.