Cyber Resilience

CVE-2021-37866

MediumPublic PoC

Published: 18 January 2022

Published
18 January 2022
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 4.7 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
EPSS Score 0.0019 40.8th percentile
Risk Priority 10 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-37866 is a medium-severity Insufficient Session Expiration (CWE-613) vulnerability in Mattermost Mattermost Boards. Its CVSS base score is 4.7 (Medium).

Operationally, ranked at the 40.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Mattermost Boards plugin v0.10.0 and earlier fails to invalidate a session on the server-side when a user logged out of Boards, which allows an attacker to reuse old session token for authorization.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

mattermost
mattermost boards
≤ 0.10.0

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.

addresses: CWE-613

Locks the device (typically after inactivity) until re-authentication, addressing insufficient session expiration by preventing indefinite access.

addresses: CWE-613

Automatically terminating sessions after a defined period directly enforces session expiration, preventing indefinite session lifetimes that attackers can exploit.

addresses: CWE-613

Re-authentication after inactivity or time-based triggers prevents indefinite use of potentially hijacked or stale sessions.

addresses: CWE-613

Terminating sessions and network connections upon completion prevents insufficient session expiration.

addresses: CWE-613

Directly enforces termination of network sessions after inactivity or end-of-session, preventing indefinite session lifetime.

addresses: CWE-613

Consistent clocks across systems allow session expiration and timeout enforcement to function as intended in distributed environments.

addresses: CWE-613

When the non-persistent artifact is a session or connection, mandatory termination implements the missing expiration that CWE-613 describes.

addresses: CWE-613

Timed refresh of session-related information or on-demand generation plus deletion implements proper session expiration.

References