Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-4858
StatePUBLISHED
AssignerMattermost
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-21 09:16:30 UTC
Updated2026-05-21 19:43:31 UTC
DescriptionMattermost 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

Risk And Classification

Primary CVSS: v3.1 9.9 CRITICAL from [email protected]

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

EPSS: 0.000460000 probability, percentile 0.142740000 (date 2026-05-27)

Problem Types: CWE-22 | CWE-22 CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary9.9CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1[email protected]Secondary8HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
3.1CNACVSS8HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Mattermost Mattermost Server All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mattermost Mattermost affected 11.6.0 11.6.0 semver Not specified
CNA Mattermost Mattermost affected 11.5.0 11.5.3 semver Not specified
CNA Mattermost Mattermost affected 11.4.0 11.4.4 semver Not specified
CNA Mattermost Mattermost affected 10.11.0 10.11.14 semver Not specified
CNA Mattermost Mattermost unaffected 11.7.0 Not specified
CNA Mattermost Mattermost unaffected 11.6.1 Not specified
CNA Mattermost Mattermost unaffected 11.5.4 Not specified
CNA Mattermost Mattermost unaffected 11.4.5 Not specified
CNA Mattermost Mattermost unaffected 10.11.15 Not specified

References

ReferenceSourceLinkTags
mattermost.com/security-updates [email protected] mattermost.com Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: daw10 (en)

Additional Advisory Data

Solutions

CNA: Update Mattermost to versions 11.7.0, 11.6.1, 11.5.4, 11.4.5, 10.11.15 or higher.

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