Cyber Resilience

CVE-2021-3138

HighPublic PoC

Published: 14 January 2021

Published
14 January 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0271 86.2th percentile
Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-3138 is a high-severity Improper Restriction of Excessive Authentication Attempts (CWE-307) vulnerability in Discourse Discourse. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 13.8% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

In Discourse 2.7.0 through beta1, a rate-limit bypass leads to a bypass of the 2FA requirement for certain forms.

CWE(s)

Related Threats

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

Affected Assets

discourse
discourse
2.7.0 · ≤ 2.6.0

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-307

This control directly enforces limits on consecutive invalid logon attempts and automatic response (e.g., lockout) to prevent brute-force exploitation of authentication mechanisms.

addresses: CWE-307

Specific conditions can include excessive failed attempts, triggering stronger authentication that restricts brute-force exploitation.

References