What is CVE-2023-6458?

Mattermost webapp fails to validate route parameters in/ /channels/ allowing an attacker to perform a client-side path traversal.

How severe is CVE-2023-6458?

CVE-2023-6458 has a CVSS score of 7.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-6458?

CVE-2023-6458 affects the following packages: github.com/mattermost/mattermost-server/v6 (Go), github.com/mattermost/mattermost/server/v8 (Go), github.com/mattermost/mattermost/server/v8 (Go), github.com/mattermost/mattermost/server (Go). Ecosystems affected: Go.

How do I fix CVE-2023-6458?

Update github.com/mattermost/mattermost-server/v6 to 7.8.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-6458 is resolved across your whole dependency graph.

How do I detect CVE-2023-6458 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/v6, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-6458 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2023-6458 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-6458 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 CVE-2023-6458?

CVE-2023-6458 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 51th 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 CVE-2023-6458?

CVE-2023-6458 is classified as CWE-74 (CWE-74), Path Traversal (CWE-22). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2023-6458 published, and has it been updated?

CVE-2023-6458 was published on December 6, 2023 and was last updated on October 28, 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

HIGH severity

CVE-2023-6458 — mattermost-server

HIGH

CVE-2023-6458 is a high-severity (CVSS 7.1) CWE-74 vulnerability in github.com/mattermost/mattermost-server/v6. A fix is available for github.com/mattermost/mattermost-server/v6 — see the affected versions and patch details below.

Client side path traversal due to lack of route parameters validation

Also known asBIT-mattermost-2023-6458GHSA-7664-hcp7-f497

Published

Dec 6, 2023

Updated

Oct 28, 2026

Affected

4 pkgs

Patched

4 / 4

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs51th percentile — riskier than 51% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

4 pkgs affected

🐹github.com/mattermost/mattermost-server/v6🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8🐹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

Mattermost webapp fails to validate route parameters in/<TEAM_NAME>/channels/<CHANNEL_NAME> allowing an attacker to perform a client-side path traversal.

Affected Packages

4 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/mattermost/mattermost-server/v6`	all versions	7.8.14`go get github.com/mattermost/mattermost-server/v6@v7.8.14`
🐹Go	`github.com/mattermost/mattermost/server/v8`	all versions	8.1.5`go get github.com/mattermost/mattermost/server/v8@v8.1.5`
🐹Go	`github.com/mattermost/mattermost/server/v8`	≥ 9.0.0&&< 9.0.3	9.0.3`go get github.com/mattermost/mattermost/server/v8@v9.0.3`
🐹Go	`github.com/mattermost/mattermost/server`	≥ 9.1.0&&< 9.1.2	9.1.2`go get github.com/mattermost/mattermost/server@v9.1.2`

Affected Products

1 product · 4 configurations

Application

mattermost servermattermost

≥ 9.1.0 && < 9.1.2

range

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/v6, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/mattermost/mattermost-server/v6 to 7.8.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-6458 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

Mattermost webapp fails to validate route parameters in/<TEAM_NAME>/channels/<CHANNEL_NAME> allowing an attacker to perform a client-side path traversal.

O3 Security · Impact-Aware SCA

Is CVE-2023-6458 in your dependencies?

Find it across Go, including transitive dependencies.

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CVSS Score

7.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

High

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

High

Availability

Low

Raw vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:H/A:L

CWE Classification

CWE-74CWE-74 CWE-22Path Traversal

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Dec 6, 2023

Last updated

Oct 28, 2026

Identifiers

CVE-2023-6458

GHSA-7664-hcp7-f497

BIT-mattermost-2023-6458

References

Advisorygithub.com · CVE 2023 6458.json Advisorynvd.nist.gov · CVE 2023 6458 Webmattermost.com · security updates Packagegithub.com · mattermost

Related vulnerabilities

This CVE is high severity — higher than any of the other 8 CVEs affecting v6 (highest there: moderate).

CVE-2025-11776CVE-2025-11777CVE-2025-53971CVE-2025-36530CVE-2025-8402CVE-2025-49222CVE-2025-47870CVE-2025-8023

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 28, 2026