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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-4858

40
FAUCET Score

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

First published: May 21, 2026Last modified: May 21, 2026

Impacted Technologies

VendorProductVersion(s)CPE
>= 10.11.0, < 10.11.15CPE matchmatch criteria
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
>= 11.4.0, < 11.4.5CPE matchmatch criteria
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
>= 11.5.0, < 11.5.4CPE matchmatch criteria
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
11.6.0CPE matchmatch criteria
cpe:2.3:a:mattermost:mattermost_server:11.6.0:*:*:*:*:*:*:*
>= 10.11.0, <= 10.11.14CPE match
cpe:2.3:a:mattermost:mattermost:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.0HIGH

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.3
Impact Score
6.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.33%
Probability of exploitation in next 30 days
EPSS Percentile
25.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0033 is in the 13th percentile among its peer group of 1,124 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 1.0 Bluesky, 0.5 Mastodon, and 1.6 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

gopatch availablevia ghsa
Product: github.com/mattermost/mattermost-serverFixed in: 11.6.1
gopatch availablevia ghsa
Product: github.com/mattermost/mattermost-serverFixed in: 11.5.4
gopatch availablevia ghsa
Product: github.com/mattermost/mattermost-serverFixed in: 11.4.5
gopatch availablevia ghsa
Product: github.com/mattermost/mattermost-serverFixed in: 10.11.15

Vendor Advisories (1)

goGHSA-c4r7-j7pp-r8mphigh

Mattermost has a Path Traversal issue

May 21, 2026

References

mattermost.com / security-updates
Vendor Advisory