CVE-2021-37859
CVE-2021-37859 is a high-severity vulnerability in Mattermost with a CVSS 3.x base score of 7.1. 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-79.
Key facts
- Severity: High (CVSS 3.x base score 7.1)
- CVSS v2: 4.3
- EPSS exploit prediction: 3% (87th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-79
- Affected product: Mattermost
- Published:
- Last modified:
Description
Fixed a bypass for a reflected cross-site scripting vulnerability affecting OAuth-enabled instances of Mattermost.
Frequently asked questions
- What is CVE-2021-37859?
- Fixed a bypass for a reflected cross-site scripting vulnerability affecting OAuth-enabled instances of Mattermost.
- How severe is CVE-2021-37859?
- CVE-2021-37859 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability low.
- Is CVE-2021-37859 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-37859?
- CVE-2021-37859 affects Mattermost. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-37859?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2021-37859 published?
- CVE-2021-37859 was published on 2021-08-05 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:mattermost:mattermost:*:*:*:*:*:*:*:*
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