Home/CVE/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
CVE

CVE-2025-8402

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

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.

MEDIUM · CVSS 4.9 EPSS 0.00155
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-1287Improper Validation of Specified Type of Input
CWE-476NULL Pointer Dereference
▤

Affected Products & Versions

5
mattermost server>= 9.11.0 and < 9.11.18
mattermost server>= 10.5.0 and < 10.5.9
mattermost server>= 10.8.0 and < 10.8.4
mattermost server>= 10.9.0 and < 10.9.4
mattermost serverall versions
▤

Affected Packages

4
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Go github.com/mattermost/mattermost-server MODERATE fixed in 10.8.4
Go github.com/mattermost/mattermost-server/v5 MODERATE
Go github.com/mattermost/mattermost-server/v6 MODERATE
Go github.com/mattermost/mattermost/server/v8 MODERATE fixed in 8.0.0-20250708173752-d6b35c41f0ae5
▣

Scoring & Timeline

4.9
MEDIUM · CVSS v3.1 · responsibledisclosure@mattermost.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD21 Aug 2025 · 05:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://mattermost.com/security-updatesVendor Advisory
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