CVE-2026-3473 json
Improper file ownership validation in the Boards API allows unauthorised file access
published 5mo ago modified 3mo ago also GHSA-7pf2-9c95-w332 , GO-2026-5817 , EUVD-2026-31429
- cvss
- 5.9
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.1%
- EPSS 0.1% chance of exploitation in 30 days, percentile 4%
- 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 validate file ownership and access control, which allows an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs.. Mattermost Advisory ID: MMSA-2026-00620
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
Is CVE-2026-3473 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 5mo ago
Exploit prediction
0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N |
| NVD | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N |
| GitHub | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/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-639 Authorization Bypass Through User-Controlled Key
References
-
mattermost.com
/security-updates
vendor-advisory, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-3473
advisory
-
github.com
/mattermost/mattermost
package
-
github.com
/advisories/GHSA-7pf2-9c95-w332
advisory
Sources
- CVE List CVE-2026-3473
- GitHub Advisory GHSA-7pf2-9c95-w332
- NVD CVE-2026-3473
- OSV GO-2026-5817
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.