How severe is CVE-2021-37866?

CVE-2021-37866 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-37866 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-37866?

CVE-2021-37866 affects Mattermost Mattermost Boards. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-37866?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-37866 published?

CVE-2021-37866 was published on 2022-01-18 and last updated on 2026-06-17.

CVE-2021-37866

CVE-2021-37866 is a medium-severity vulnerability in Mattermost Mattermost Boards with a CVSS 3.x base score of 4.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-613.

Key facts

Severity: Medium (CVSS 3.x base score 4.7)
CVSS v2: 5.0
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-613
Affected product: Mattermost Mattermost Boards
Published: 2022-01-18
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-37866?: 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.
How severe is CVE-2021-37866?: CVE-2021-37866 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-37866 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-37866?: CVE-2021-37866 affects Mattermost Mattermost Boards. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-37866?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-37866 published?: CVE-2021-37866 was published on 2022-01-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mattermost:mattermost_boards:*:*:*:*:*:*:*:*

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