Cyber Resilience

CVE-2026-2462

Medium

Published: 16 March 2026

Published
16 March 2026
Modified
18 March 2026
KEV Added
—
Patch
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CVSS Score v3.1 6.6 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L
EPSS Score 0.0020 42.6th percentile
Risk Priority 13 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-2462 is a medium-severity Incorrect Authorization (CWE-863) vulnerability in Mattermost Mattermost Server. Its CVSS base score is 6.6 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 42.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to restrict plugin installation on CI test instances with default admin credentials which allows an unauthenticated attacker to achieve remote code execution and exfiltrate sensitive configuration data including…

more

AWS and SMTP credentials via uploading a malicious plugin after changing the import directory. Mattermost Advisory ID: MMSA-2025-00528

CWE(s)
CWE-863

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1078.001 Default Accounts Stealth
Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1505.003 Web Shell Persistence
Adversaries may backdoor web servers with web shells to establish persistent access to systems.
attack.mitre.org →
Why these techniques?

Vulnerability enables unauthenticated RCE on public-facing Mattermost via default admin creds and malicious plugin upload (T1190 + T1078.001 + T1505.003).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

Affected Assets

mattermost
mattermost server
10.11.0 — 10.11.11 · 11.2.0 — 11.2.3 · 11.3.0 — 11.3.1

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AC-1 Policy and Procedures
addresses: CWE-863

Periodic review and update of procedures reduces incorrect authorization implementations over time.

AC-13 Supervision and Review — Access Control
addresses: CWE-863

Supervision identifies cases where authorization logic incorrectly permits unauthorized actions.

AC-16 Security and Privacy Attributes
addresses: CWE-863

Defining permitted attribute values and auditing modifications reduces the chance of incorrect authorization outcomes due to tampered or missing labels.

AC-17 Remote Access
addresses: CWE-863

The authorization process and usage restrictions help prevent incorrect authorization for remote access types.

AC-18 Wireless Access
addresses: CWE-863

Establishing configuration and connection requirements helps ensure correct rather than incorrect authorization for wireless access.

AC-19 Access Control for Mobile Devices
addresses: CWE-863

Establishing connection authorization processes for mobile devices helps ensure authorization decisions are correctly implemented rather than incorrect.

AC-2 Account Management
addresses: CWE-863

Monitoring account use, notifying on changes, and reviewing accounts for compliance corrects incorrect authorization assignments.

AC-20 Use of External Systems
addresses: CWE-863

Ensures authorization decisions for external system use are correctly implemented and enforced.

References