CVE-2025-47871
MEDIUMCVE-2025-47871 is a medium-severity (CVSS 4.3) CWE-863 vulnerability in github.com/mattermost/mattermost-server. O3 Security confirms whether CVE-2025-47871 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Mattermost Playbooks exposes private channel metadata to unauthorized users via run metadata API
Blast Radius
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 properly validate channel membership when retrieving playbook run metadata, allowing authenticated users who are playbook members but not channel members to access sensitive information about linked private channels including channel name, display name, and participant count through the run metadata API endpoint.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/mattermost/mattermost-server | all versions | 0.0.0-20250513065225-4ae5d647fb88 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | all versions | 8.0.0-20250513065225-4ae5d647fb88 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 9.11.0&&< 9.11.16 | 9.11.16 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 10.5.0&&< 10.5.6 | 10.5.6 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 10.6.0&&< 10.6.6 | 10.6.6 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 10.7.0&&< 10.7.3 | 10.7.3 |
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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/mattermost/mattermost-server to 0.0.0-20250513065225-4ae5d647fb88 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-47871 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 pinpoints whether CVE-2025-47871 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2025-47871. 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-2025-47871 in your dependencies?
O3 detects CVE-2025-47871 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.