CVE-2021-33582

Name: CVE-2021-33582
Creator: NVD / NIST
Published: 2021-09-01T06:15:06.387+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 3.07%

Last modified Jun 17, 2026

CVE-2021-33582 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang) via input that is mishandled during hash-table interaction. Because there are many insertions into a single bucket, strcmp becomes slow. EPSS estimates a 3.07% chance of exploitation in the next 30 days.

Description

Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang) via input that is mishandled during hash-table interaction. Because there are many insertions into a single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

3.07%

86.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-407

Affected Software

Vendor	Product	Versions
Cyrus	Imap	< 3.0.16
Cyrus	Imap	>= 3.2.0, < 3.2.8
Cyrus	Imap	>= 3.4.0, < 3.4.2
Fedoraproject	Fedora	34
Fedoraproject	Fedora	35
Debian	Debian Linux	9.0

References

https://cyrus.topicbox.com/groups/announce/T3dde0a2352462975-M1386fc44adf967e072f8df13/cyrus-imap-3-4-2-3-2-8-and-3-0-16-releasedPatch, Vendor Advisory
https://github.com/cyrusimap/cyrus-imapd/commits/masterPatch, Third Party Advisory
https://github.com/cyrusimap/cyrus-imapd/security/advisoriesNot Applicable, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/06/msg00013.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6HEO3RURJW6NLIXS7NK5PVU6MGHC4SCM/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WJZB45QBUN7CZFGOWCZYUYACNBTX7LVS/
https://www.cyrusimap.org/imap/download/release-notes/index.htmlPatch, Release Notes, Vendor Advisory
https://cyrus.topicbox.com/groups/announce/T3dde0a2352462975-M1386fc44adf967e072f8df13/cyrus-imap-3-4-2-3-2-8-and-3-0-16-releasedPatch, Vendor Advisory
https://github.com/cyrusimap/cyrus-imapd/commits/masterPatch, Third Party Advisory
https://github.com/cyrusimap/cyrus-imapd/security/advisoriesNot Applicable, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/06/msg00013.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6HEO3RURJW6NLIXS7NK5PVU6MGHC4SCM/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WJZB45QBUN7CZFGOWCZYUYACNBTX7LVS/
https://www.cyrusimap.org/imap/download/release-notes/index.htmlPatch, Release Notes, Vendor Advisory

Timeline

Published: Sep 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-33582?

How severe is CVE-2021-33582?

CVE-2021-33582 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 3.07% probability of exploitation in the next 30 days.

How do I fix CVE-2021-33582?

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-2021-33582?

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

Scan your code now

Source: NVD / NIST