CVE-2026-3636 json
Sanitize team member data returned by API
published 2026-05-22 5 mo ago modified 2026-07-23 3 mo ago also GHSA-ffpr-pfr4-g354 , GO-2026-5818 , EUVD-2026-31428
- 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 8%
- public exploits
- 0
- none known
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to sanitize team member data when returned via API to users without elevated permissions which allows a user without permissions to get data about team members roles via invoking various team API endpoints.. Mattermost Advisory ID: MMSA-2026-00626
Patch / fix
- go github.com/mattermost/mattermost-server 10.11.15, 10.11.15+incompatible, 11.4.5, 11.4.5+incompatible, 11.5.4, 11.5.4+incompatible, 11.6.1, 11.6.1+incompatible
- Mattermost Mattermost 10.11.15, 11.4.5, 11.5.4, 11.6.1, 11.7.0
- govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
opensuse advisories openSUSE-SU-2026:21483-1
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 5 mo ago
Exploit prediction
0.18% chance of exploitation in the next 30 days, higher than 8% 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: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 | >=11.6.0, <11.6.1 >=11.5.0, <11.5.4 >=11.4.0, <11.4.5 >=10.11.0, <10.11.15 >=10.11.0+incompatible, <10.11.15+incompatible >=11.4.0+incompatible, <11.4.5+incompatible >=11.5.0+incompatible, <11.5.4+incompatible >=11.6.0+incompatible, <11.6.1+incompatible |
11.6.1 11.5.4 11.4.5 10.11.15 10.11.15+incompatible 11.4.5+incompatible 11.5.4+incompatible 11.6.1+incompatible |
Affected products
- Mattermost Mattermost
Classification
- Weakness
-
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
References
-
mattermost.com
/security-updates
vendor-advisory, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-3636
advisory
-
github.com
/mattermost/mattermost
package
-
github.com
/advisories/GHSA-ffpr-pfr4-g354
advisory
Sources
- CVE List CVE-2026-3636
- GitHub Advisory GHSA-ffpr-pfr4-g354
- NVD CVE-2026-3636
- OSV GO-2026-5818
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.