Security readout for executives and security teams
Plain-English summary
Mattermost Boards had an information disclosure issue where a Boards API could expose all users' email addresses. This is a privacy and phishing-enablement risk, not a system takeover issue based on the supplied CVSS and description.
Executive priority
Handle as a moderate privacy and fraud-risk item. It does not indicate code execution or outage risk, but exposed employee email lists can support phishing, impersonation, and targeted social engineering.
Technical view
CVE-2021-37867 is a CWE-200 exposure in Mattermost Boards plugin v0.10.0 and earlier. The cited description says one Boards API failed to protect user email addresses. CVSS 3.1 is 4.3 with network access, low complexity, low confidentiality impact, and no integrity or availability impact.
Likely exposure
Exposure is likely limited to Mattermost deployments using the Boards plugin v0.10.0 or earlier. The bundle lists affected versions including 0.9.5, 0.8.4, 0.7.5, and unspecified earlier releases.
Exploitation context
The source bundle does not cite CISA KEV or any active exploitation report. The description says authenticated and unauthorized users could access email addresses, while the CVSS vector lists low privileges required, so access requirements are not fully clear.
Researcher notes
Evidence is limited to the CVE description and Mattermost security update reference. No exploit details, patch version, or active exploitation source is included. Note the mismatch between description wording and CVSS privileges when assessing reachability.
Mitigation direction
- Inventory Mattermost instances using the Boards plugin.
- Prioritize upgrades or remediation for Boards v0.10.0 and earlier.
- Check Mattermost security updates for the vendor-designated fixed version or mitigation.
- Limit Boards access where business operations allow.
- Treat exposed emails as potential phishing targeting data.
Validation and detection
- Confirm the installed Mattermost Boards plugin version on each instance.
- Compare deployed versions against v0.10.0 and earlier exposure criteria.
- Review Mattermost security updates for official remediation status.
- Check access logs for unusual Boards API user-metadata access.
- Validate that email addresses are not exposed to unauthorized users after remediation.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-200: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-37867 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N2.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://mattermost.com/security-updates/CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Exposure of Sensitive Information to an Unauthorized Actor
Exposure of Sensitive Information to an Unauthorized Actor represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.