CVE-2025-49222 json
Mattermost Shared Channel Upload Type Validation Bypass
published 2025-08-21 14 mo ago modified 2026-06-17 4 mo ago also GHSA-q453-638c-h4mr , GO-2025-3904 , EUVD-2025-25418
- cvss
- 6.8
- 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 23%
- public exploits
- 0
- none known
Summary
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2, 10.10.x <= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.
Patch / fix
- go github.com/mattermost/mattermost-server 9.11.18, 9.11.18+incompatible, 10.5.9, 10.5.9+incompatible, 10.8.4, 10.8.4+incompatible, 10.9.3, 10.9.3+incompatible, 10.10.1, 10.10.1+incompatible
- go github.com/mattermost/mattermost/server/v8 8.0.0-20250708173752-d6b35c41f0ae5
- Mattermost Mattermost 9.11.18, 10.5.9, 10.8.4, 10.9.3, 10.10.1, 10.11.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 14 mo ago
Exploit prediction
0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N |
| NVD | 3.1 | 6.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N |
| GitHub | 3.1 | 6.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/mattermost/mattermost-server | >=10.8.0, <10.8.4 >=10.5.0, <10.5.9 >=9.11.0, <9.11.18 >=10.9.0, <10.9.3 >=10.10.0, <10.10.1 >=9.11.0+incompatible, <9.11.18+incompatible >=10.5.0+incompatible, <10.5.9+incompatible >=10.8.0+incompatible, <10.8.4+incompatible >=10.9.0+incompatible, <10.9.3+incompatible >=10.10.0+incompatible, <10.10.1+incompatible |
10.8.4 10.5.9 9.11.18 10.9.3 10.10.1 9.11.18+incompatible 10.5.9+incompatible 10.8.4+incompatible 10.9.3+incompatible 10.10.1+incompatible |
| go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20250708173752-d6b35c41f0ae5 all versions |
8.0.0-20250708173752-d6b35c41f0ae5 |
| go | github.com/mattermost/mattermost-server/v5 | <=5.39.3 all versions |
no fix listed |
| go | github.com/mattermost/mattermost-server/v6 | <=5.7.2 all versions |
no fix listed |
Affected products
- Mattermost Mattermost
Classification
- Weakness
-
- CWE-434 Unrestricted Upload of File with Dangerous Type
References
-
mattermost.com
/security-updates
web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2025-49222
advisory
-
github.com
/mattermost/mattermost
package
-
pkg.go.dev
/vuln/GO-2025-3904
web
-
github.com
/advisories/GHSA-q453-638c-h4mr
advisory
Sources
- CVE List CVE-2025-49222
- GitHub Advisory GHSA-q453-638c-h4mr
- NVD CVE-2025-49222
- OSV GO-2025-3904
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