High severity8.0NVD Advisory· Published May 21, 2026· Updated May 21, 2026
CVE-2026-4858
CVE-2026-4858
Description
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to check integration URL for path traversal which allows an malicious authenticated user to call an arbitrary API via system admin Mattermost auth token using via path traversal in integration action URL.. Mattermost Advisory ID: MMSA-2026-00640
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/mattermost/mattermost-serverGo | >= 11.6.0, < 11.6.1 | 11.6.1 |
github.com/mattermost/mattermost-serverGo | >= 11.5.0, < 11.5.4 | 11.5.4 |
github.com/mattermost/mattermost-serverGo | >= 11.4.0, < 11.4.5 | 11.4.5 |
github.com/mattermost/mattermost-serverGo | >= 10.11.0, < 10.11.15 | 10.11.15 |
Affected products
3cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*range: >=10.11.0,<10.11.15
- cpe:2.3:a:mattermost:mattermost_server:11.6.0:*:*:*:*:*:*:*
- (no CPE)range: <=11.6.0
Patches
Vulnerability mechanics
References
3- github.com/advisories/GHSA-c4r7-j7pp-r8mpghsaADVISORY
- mattermost.com/security-updatesnvdVendor AdvisoryWEB
- nvd.nist.gov/vuln/detail/CVE-2026-4858ghsaADVISORY
News mentions
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