What is CVE-2021-36093?

CVE-2021-36093 is a medium-severity vulnerability in Otrs, classified under Incorrect Regular Expression. CVSS score: 5.3/10. Published 2021-09-06.

How severe is CVE-2021-36093?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Otrs

CVE-2021-36093

It's possible to create an email which can be stuck while being processed by PostMaster filters, causing DoS. 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 7.0.28 and prior versions; 8.0.x version 8.0.15 and prior versions.

Published 2021-09-06 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.011 (64.5th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 64.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Otrs
Otrs Ag — versions 7.0.x, 8.0.x
Otrs Ag ((Otrs)) Community Edition — versions 6.0.1

Weakness classification (CWE)

CWE-185 — Incorrect Regular Expression

References

otrs.com/release-notes/otrs-security-advisory-2021-16/ (Vendor Advisory)

Frequently asked questions

What is CVE-2021-36093?: CVE-2021-36093 is a medium-severity vulnerability in Otrs, classified under Incorrect Regular Expression. CVSS score: 5.3/10. Published 2021-09-06.
How severe is CVE-2021-36093?: Medium severity. CVSS v3 base score is 5.3 out of 10.