GHSA-pfw6-5rx3-xh3c — v8
MEDIUMGHSA-pfw6-5rx3-xh3c is a medium-severity (CVSS 4.3) vulnerability in github.com/mattermost/mattermost/server/v8. A fix is available for github.com/mattermost/mattermost/server/v8 — see the affected versions and patch details below.
Mattermost fails to check the "invite_guest" permission
Exploitation Status
No confirmed exploitation observed yet
- 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 GHSA-pfw6-5rx3-xh3c.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-pfw6-5rx3-xh3c by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
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 fails to check the "invite_guest" permission when inviting guests of other teams to a team, allowing a member with permissions to add other members but not to add guests to add a guest to a team as long as the guest was already a guest in another team of the server
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 9.4.0&&< 9.4.2 | 9.4.2go get github.com/mattermost/mattermost/server/v8@v9.4.2 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 9.3.0&&< 9.3.1 | 9.3.1go get github.com/mattermost/mattermost/server/v8@v9.3.1 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 9.2.0&&< 9.2.5 | 9.2.5go get github.com/mattermost/mattermost/server/v8@v9.2.5 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | all versions | 8.1.9go get github.com/mattermost/mattermost/server/v8@v8.1.9 |
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/v8, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/mattermost/mattermost/server/v8 to 9.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pfw6-5rx3-xh3c 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.
Frequently Asked Questions
Is GHSA-pfw6-5rx3-xh3c in your dependencies?
Find it across Go, including transitive dependencies.