How severe is GHSA-h5v9-xw2g-7hrq?

GHSA-h5v9-xw2g-7hrq has a CVSS score of 5.4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-h5v9-xw2g-7hrq?

GHSA-h5v9-xw2g-7hrq affects the following packages: github.com/mattermost/mattermost/server/v8 (Go), github.com/mattermost/mattermost/server/v8 (Go), github.com/mattermost/mattermost/server/v8 (Go), github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost/server/v8 (Go). Ecosystems affected: Go.

How do I fix GHSA-h5v9-xw2g-7hrq?

Update github.com/mattermost/mattermost/server/v8 to 10.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h5v9-xw2g-7hrq is resolved across your whole dependency graph.

How do I detect GHSA-h5v9-xw2g-7hrq in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost/server/v8. 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.

How do I mitigate GHSA-h5v9-xw2g-7hrq if there is no patch (or I can't update yet)?

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 does O3 Security protect against GHSA-h5v9-xw2g-7hrq?

O3 pinpoints whether GHSA-h5v9-xw2g-7hrq is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-h5v9-xw2g-7hrq actively exploited in the wild?

No public exploit code has been indexed for GHSA-h5v9-xw2g-7hrq yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-h5v9-xw2g-7hrq?

GHSA-h5v9-xw2g-7hrq has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 9th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-h5v9-xw2g-7hrq?

GHSA-h5v9-xw2g-7hrq is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-h5v9-xw2g-7hrq published, and has it been updated?

GHSA-h5v9-xw2g-7hrq was published on March 21, 2025 and was last updated on February 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

GHSA-h5v9-xw2g-7hrq

MEDIUM

GHSA-h5v9-xw2g-7hrq is a medium-severity (CVSS 5.4) CWE-863 vulnerability in github.com/mattermost/mattermost/server/v8. O3 Security confirms whether GHSA-h5v9-xw2g-7hrq is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Mattermost allows members with permission to convert public channels to private and convert private to public

Also known asBIT-mattermost-2025-27933CVE-2025-27933GO-2025-3556

Published

Mar 21, 2025

Updated

Feb 4, 2026

Affected

5 pkgs

Patched

5 / 5

Exploits

None indexed

Exploitation data as of Aug 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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-h5v9-xw2g-7hrq.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs9th percentile — riskier than 9% of all scored CVEsHighest risk

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

GHSA-h5v9-xw2g-7hrq 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 0 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

5 pkgs affected

🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost-server🐹github.com/mattermost/mattermost/server/v8

Real-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 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to to enforce channel conversion restrictions, which allows members with permission to convert public channels to private ones to also convert private ones to public.

Affected Packages

5 total 5 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/mattermost/mattermost/server/v8`	≥ 10.4.0&&< 10.4.3	10.4.3
🐹Go	`github.com/mattermost/mattermost/server/v8`	≥ 10.3.0&&< 10.3.4	10.3.4
🐹Go	`github.com/mattermost/mattermost/server/v8`	≥ 9.11.0&&< 9.11.9	9.11.9
🐹Go	`github.com/mattermost/mattermost-server`	all versions	9.11.9
🐹Go	`github.com/mattermost/mattermost/server/v8`	all versions	8.0.0-20250218135018-e644e3c8e393

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost/server/v8. 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/v8 to 10.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h5v9-xw2g-7hrq 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 GHSA-h5v9-xw2g-7hrq 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 GHSA-h5v9-xw2g-7hrq. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is GHSA-h5v9-xw2g-7hrq in your dependencies?

O3 detects GHSA-h5v9-xw2g-7hrq across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works