CVE-2026-2476
Published: 16 March 2026
Summary
CVE-2026-2476 is a high-severity Exposure of Sensitive Information to an Unauthorized Actor (CWE-200) vulnerability in Mattermost Ms Teams. Its CVSS base score is 7.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Unsecured Credentials (T1552); ranked at the 10.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
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.
Automated marking applies security attributes to system outputs, making it harder for attackers to exploit unmarked sensitive information leading to unauthorized exposure.
Proper attribute retention and permitted-value enforcement limits unauthorized actors from accessing sensitive information lacking correct labels.
Prevents unauthorized exposure of sensitive information by prohibiting untrusted external systems from processing or storing it.
By enforcing authorization matching prior to sharing, the control reduces the risk of exposing sensitive information to unauthorized actors.
Review and removal of nonpublic information from publicly accessible systems directly prevents exposure of sensitive data to unauthorized actors.
Data mining protection mechanisms detect and block unauthorized bulk extraction of sensitive data, directly mitigating exposure to unauthorized actors.
Literacy training teaches users to recognize and avoid actions that result in unauthorized exposure of sensitive information.
Retaining and monitoring training records confirms personnel have completed privacy and security awareness training on handling sensitive data, reducing the chance of unauthorized exposure due to lack of knowledge.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability exposes unmasked sensitive plugin configuration values (typically credentials/secrets) in exported support packets and configuration data, directly enabling adversaries to obtain unsecured credentials from application configuration.
NVD Description
Mattermost Plugins versions <=2.0.3.0 fail to properly mask sensitive configuration values which allows an attacker with access to support packets to obtain original plugin settings via exported configuration data. Mattermost Advisory ID: MMSA-2026-00606
Deeper analysisAI
CVE-2026-2476 is a vulnerability in Mattermost Plugins versions <=2.0.3.0 that results from a failure to properly mask sensitive configuration values. This flaw allows an attacker with access to support packets to obtain the original plugin settings via exported configuration data. The issue is tracked under Mattermost Advisory ID MMSA-2026-00606 and carries a CVSS score of 7.6 (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:N), with associated CWEs CWE-200 and NVD-CWE-noinfo.
Exploitation requires high privileges (PR:H) on the affected Mattermost instance and is feasible over the network (AV:N) with low attack complexity (AC:L) and no user interaction (UI:N). An attacker can achieve high confidentiality impact (C:H) with a changed scope (S:C), enabling the exposure of sensitive plugin configuration data, while integrity impact remains low (I:L) and availability is unaffected (A:N).
Mitigation details are available in Mattermost Advisory MMSA-2026-00606 and the security updates page at https://mattermost.com/security-updates.
Details
- CWE(s)