CVE-2021-21439

Name: CVE-2021-21439
Creator: NVD / NIST
Published: 2021-06-14T08:15:10.097+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.98%

Last modified Jun 17, 2026

CVE-2021-21439 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.98% chance of exploitation in the next 30 days.

Description

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 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.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS Probability

0.98%

57.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Otrs	Otrs	>= 6.0.1, <= 6.0.30
Otrs	Otrs	>= 7.0.0, < 7.0.27
Otrs	Otrs	>= 8.0.0, < 8.0.14

References

Timeline

Published: Jun 14, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21439?

How severe is CVE-2021-21439?

CVE-2021-21439 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.98% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21439?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21439?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST