Cyber Resilience

CVE-2021-21439

Medium

Published: 14 June 2021

Published
14 June 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS Score 0.0035 57.7th percentile
Risk Priority 13 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-21439 is a medium-severity Improper Check for Unusual or Exceptional Conditions (CWE-754) vulnerability in Otrs Otrs. Its CVSS base score is 6.5 (Medium).

Operationally, ranked in the top 42.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

DoS attack can be performed when an email contains specially designed URL in the body. It can lead to the high CPU usage and cause low quality of service, or in extreme case bring the system to a halt. This…

more

issue affects: OTRS AG ((OTRS)) Community Edition 6.0.x version 6.0.1 and later versions. OTRS AG OTRS 7.0.x version 7.0.26 and prior versions; 8.0.x version 8.0.13 and prior versions.

CWE(s)

Related Threats

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

Affected Assets

otrs
otrs
6.0.1 — 6.0.30 · 7.0.0 — 7.0.27 · 8.0.0 — 8.0.14

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-754 CWE-755

Requires detection and response to audit logging failures as an unusual or exceptional condition.

addresses: CWE-754 CWE-755

Implements detection of unusual or exceptional conditions followed by safe mode entry, reducing the window for exploitation of unchecked conditions.

addresses: CWE-754 CWE-755

Training ensures users perform required checks for unusual or exceptional conditions as part of contingency roles, limiting attacker leverage from skipped validations.

addresses: CWE-754 CWE-755

IR testing directly validates checks for unusual or exceptional conditions that could indicate security incidents.

addresses: CWE-755 CWE-754

Enforces structured response to exceptional conditions so the system cannot remain in an unsafe state.

addresses: CWE-754 CWE-755

MTTF determination forces explicit checks for conditions that precede predictable component failure.

addresses: CWE-755

An updated contingency plan defines current actions for exceptional conditions, reducing the window for attackers to exploit improper handling leading to system failure.

addresses: CWE-755

Procedures ensure proper handling of exceptional conditions to support effective incident response.

References