CVE-2025-4981 is a critical-severity (CVSS 9.9) CWE-427 vulnerability in github.com/mattermost/mattermost-server. A fix is available for github.com/mattermost/mattermost-server — see the affected versions and patch details below.
Path Traversal Leading to RCE by Any Authenticated Mattermost User
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-4981.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-4981 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/mattermost/mattermost-server🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to sanitize filenames in the archive extractor which allows authenticated users to write files to arbitrary locations on the filesystem via uploading archives with path traversal sequences in filenames, potentially leading to remote code execution. The vulnerability impacts instances where file uploads and document search by content is enabled (FileSettings.EnableFileAttachments = true and FileSettings.ExtractContent = true). These configuration settings are enabled by default.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/mattermost/mattermost-server | all versions | 0.0.0-20250519205859-65aec10162f6go get github.com/mattermost/mattermost-server@v0.0.0-20250519205859-65aec10162f6 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | all versions | 8.0.0-20250519205859-65aec10162f6go get github.com/mattermost/mattermost/server/v8@v8.0.0-20250519205859-65aec10162f6 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 10.5.0&&< 10.5.6 | 10.5.6go get github.com/mattermost/mattermost/server/v8@v10.5.6 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 9.11.0&&< 9.11.16 | 9.11.16go get github.com/mattermost/mattermost/server/v8@v9.11.16 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 10.8.0&&< 10.8.1 | 10.8.1go get github.com/mattermost/mattermost/server/v8@v10.8.1 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 10.7.0&&< 10.7.3 | 10.7.3go get github.com/mattermost/mattermost/server/v8@v10.7.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/mattermost/mattermost-server to 0.0.0-20250519205859-65aec10162f6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-4981 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-4981 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-4981. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-4981 in your dependencies?
O3 Security finds CVE-2025-4981 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.