CVE-2025-8402
Nil pointer dereference in bulk import crashes server
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to validate import data which allows a system admin to crash the server via the bulk import feature.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Nil pointer dereference in bulk import crashes server
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to validate import data which allows a system admin to crash the server via the bulk import feature.
- Record
CVE-2025-8402- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-1287, CWE-476
- Updated
- 2026-11-02
EUVDEUVD-2025-25459
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to validate import data which allows a system admin to crash the server via the bulk import feature.
- Record
EUVD-2025-25459- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-h469-4fcf-p23h
Mattermost has Potential Server Crash due to Unvalidated Import Data
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to validate import data which allows a system admin to crash the server via the bulk import feature.
- Record
GHSA-h469-4fcf-p23h- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
NVD
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to validate import data which allows a system admin to crash the server via the bulk import feature.
- Record
CVE-2025-8402- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-476, CWE-1287
- Updated
- 2026-11-02
OSV
Nil pointer dereference in bulk import crashes server
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to validate import data which allows a system admin to crash the server via the bulk import feature.
- Record
CVE-2025-8402- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-1287, CWE-476
- Updated
- 2026-11-07
OSVGHSA-h469-4fcf-p23h
Mattermost has Potential Server Crash due to Unvalidated Import Data
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to validate import data which allows a system admin to crash the server via the bulk import feature.
- Record
GHSA-h469-4fcf-p23h- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
OSVGO-2025-3911 No score
Mattermost has Potential Server Crash due to Unvalidated Import Data in github.com/mattermost/mattermost-server
Mattermost has Potential Server Crash due to Unvalidated Import Data in github.com/mattermost/mattermost-server.
NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.
(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)
The additional affected modules and versions are: github.com/mattermost/mattermost/server/v8 before v8.0.0-20250708173752-d6b35c41f0ae5.
- Record
GO-2025-3911- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/mattermost/mattermost-serverGo |
10.8.0 to 10.8.3 | 10.8.4 |
github.com/mattermost/mattermost-serverGo |
10.5.0 to 10.5.8 | 10.5.9 |
github.com/mattermost/mattermost-serverGo |
10.9.0 to 10.9.3 | 10.9.4 |
github.com/mattermost/mattermost-serverGo |
10.10.0 to 10.10.0 | 10.10.1 |
github.com/mattermost/mattermost/server/v8Go |
before 8.0.0-20250708173752-d6b35c41f0ae5 | 8.0.0-20250708173752-d6b35c41f0ae5 |
github.com/mattermost/mattermost-serverGo |
9.11.0 to 9.11.17 | 9.11.18 |
github.com/mattermost/mattermost-server/v5Go |
through 5.39.3 | None known |
github.com/mattermost/mattermost-server/v6Go |
through 6.7.2 | None known |
github.com/mattermost/mattermost-serverGo |
10.8.0 up to 10.8.4 | 10.8.4 |
github.com/mattermost/mattermost-serverGo |
10.5.0 up to 10.5.9 | 10.5.9 |
Show 7 moreShow less
| Package | Affected | Fixed |
|---|---|---|
github.com/mattermost/mattermost-serverGo |
10.9.0 up to 10.9.4 | 10.9.4 |
github.com/mattermost/mattermost-serverGo |
10.10.0 up to 10.10.1 | 10.10.1 |
github.com/mattermost/mattermost-serverGo |
9.11.0 up to 9.11.18 | 9.11.18 |
github.com/mattermost/mattermost-serverGo |
9.11.0+incompatible up to 9.11.18+incompatible, 10.5.0+incompatible up to 10.5.9+incompatible, 10.8.0+incompatible up to 10.8.4+incompatible, 10.9.0+incompatible up to 10.9.4+incompatible, 10.10.0+incompatible up to 10.10.1+incompatible | 9.11.18+incompatible10.5.9+incompatible10.8.4+incompatible10.9.4+incompatible10.10.1+incompatible |
github.com/mattermost/mattermost-server/v5Go |
All versions | None known |
github.com/mattermost/mattermost-server/v6Go |
All versions | None known |
github.com/mattermost/mattermost/server/v8Go |
All versions | None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-8402 is a medium vulnerability (CVSS 4.9) in Mattermost, published August 21, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.32%, the 25th percentile. Fixed in github.com/mattermost/mattermost-server 10.8.4.