Mattermost Injection vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2023-6458: 0.64% estimated exploitation activity in the next 30 days; percentile 50.90 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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

Published by the source

6 Dec 2023, 09:30 UTC

Last modified by the source

12 Dec 2023, 21:39 UTC

Source last checked

26 Oct 2026, 15:00 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7664-hcp7-f497

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# Patch Next advisory brief: CVE-2023-6458

Advisory: Mattermost Injection vulnerability
IDs: CVE-2023-6458, GHSA-7664-hcp7-f497
Record: https://patchnext.com/advisories/cve-2023-6458 (revision 1, source checked 26 Oct 2026, 15:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/mattermost/mattermost/server/v8 9.0.3, 8.1.5; github.com/mattermost/mattermost-server/v6 7.8.14; github.com/mattermost/mattermost/server 9.1.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/mattermost/mattermost/server/v8: affected < 8.1.5; >= 9.0.0, < 9.0.3; fixed in 9.0.3, 8.1.5
- Go github.com/mattermost/mattermost-server/v6: affected < 7.8.14; fixed in 7.8.14
- Go github.com/mattermost/mattermost/server: affected >= 9.1.0, < 9.1.2; fixed in 9.1.2

## Suggested inspection (read-only)
- Go github.com/mattermost/mattermost/server/v8: check the installed version with your package manager.
- Go github.com/mattermost/mattermost-server/v6: check the installed version with your package manager.
- Go github.com/mattermost/mattermost/server: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost-server/v6, github.com/mattermost/mattermost/server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7664-hcp7-f497 (GitHub-reviewed advisory GHSA-7664-hcp7-f497 lists affected ranges: Go github.com/mattermost/mattermost-server/v6 >=0 =0 =9.0.0 =9.1.0 <9.1.2)

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