How severe is GHSA-9rr5-q43r-ccv4?

No CVSS score has been assigned to GHSA-9rr5-q43r-ccv4 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-9rr5-q43r-ccv4?

GHSA-9rr5-q43r-ccv4 affects the following packages: github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost-server (Go). Ecosystems affected: Go.

How do I fix GHSA-9rr5-q43r-ccv4?

Update github.com/mattermost/mattermost-server to 4.1.2-0.20171004201910-6be8113eb60c or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9rr5-q43r-ccv4 is resolved across your whole dependency graph.

How do I detect GHSA-9rr5-q43r-ccv4 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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-9rr5-q43r-ccv4 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.

Is GHSA-9rr5-q43r-ccv4 actively exploited in the wild?

No public exploit code has been indexed for GHSA-9rr5-q43r-ccv4 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-9rr5-q43r-ccv4?

GHSA-9rr5-q43r-ccv4 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 54th 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-9rr5-q43r-ccv4?

GHSA-9rr5-q43r-ccv4 is classified as CWE-732 (CWE-732). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-9rr5-q43r-ccv4 published, and has it been updated?

GHSA-9rr5-q43r-ccv4 was published on May 24, 2022 and was last updated on December 9, 2025. 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

Mattermost Server does not prevent System Admin from arbitrary file creationGHSA-9rr5-q43r-ccv4

Fix: mattermost/mattermost@6be8113

GHSA-9rr5-q43r-ccv4 is a CWE-732 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.

Also known asCVE-2017-18875GO-2025-4186

Published

May 24, 2022

Updated

Dec 9, 2025

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs54th percentile — riskier than 54% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

3 pkgs affected

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

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

An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2 when local storage for files is used. A System Admin can create arbitrary files.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/mattermost/mattermost-server`	all versions	4.1.2-0.20171004201910-6be8113eb60c`go get github.com/mattermost/mattermost-server@v4.1.2-0.20171004201910-6be8113eb60c`
🐹Go	`github.com/mattermost/mattermost-server`	≥ 4.2.0-rc1.0.20171004154238-fadd9514f6e7&&< 4.2.1-0.20171004194140-6d3cb2ce07fc	4.2.1-0.20171004194140-6d3cb2ce07fc`go get github.com/mattermost/mattermost-server@v4.2.1-0.20171004194140-6d3cb2ce07fc`
🐹Go	`github.com/mattermost/mattermost-server`	≥ 4.3.0-rc1&&< 4.3.0	4.3.0`go get github.com/mattermost/mattermost-server@v4.3.0`

Affected Products

1 product · 6 configurations

Application

mattermost servermattermost

≥ 4.2.0 && < 4.2.1

1 version

4.3.0

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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/mattermost/mattermost-server to 4.1.2-0.20171004201910-6be8113eb60c or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9rr5-q43r-ccv4 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

An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2 when local storage for files is used. A System Admin can create arbitrary files.