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TI-2021-12968 Aliases CVE-2021-33582GHSA-prxx-4m38-9m83

Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service…

Priority LOW 38CWE-407Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 3 fixed, 2 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-407.

Summary

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.

Why it matters now

EPSS 0.03095 87th percentileScored 2026-11-07
Fix Partial Red Hat: 3 advisoriesRed Hat: 3 fixed, 2 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 4

CPEVersionsRoleVendor
cpe:2.3:a:cyrus:imap:*:*:*:*:*:*:*:*before 3.0.16; 3.2.0 to before 3.2.8; 3.4.0 to before 3.4.2VulnerableCyrus
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*34VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*35VulnerableFedoraproject
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
  • cpe:2.3:a:cyrus:imap:*:*:*:*:*:*:*:* Versions before 3.0.16; 3.2.0 to before 3.2.8; 3.4.0 to before 3.4.2 Vulnerable ·Cyrus
  • cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian

Remediation

Red Hat 3 advisories

  • RHSA-2021:3546 Released 2021-09-15 · Red Hat rating Important
    cyrus-imapd security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) cyrus-imapd-3.0.7-16.el8_1.1, cyrus-imapd-utils-3.0.7-16.el8_1.1, cyrus-imapd-vzic-3.0.7-16.el8_1.1
  • RHSA-2021:3492 Released 2021-09-13 · Red Hat rating Important
    cyrus-imapd security update
    • Red Hat Enterprise Linux AppStream (v. 8) cyrus-imapd-3.0.7-20.el8_4.1, cyrus-imapd-utils-3.0.7-20.el8_4.1, cyrus-imapd-vzic-3.0.7-20.el8_4.1
  • RHSA-2021:3493 Released 2021-09-13 · Red Hat rating Important
    cyrus-imapd security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) cyrus-imapd-3.0.7-16.el8_2.1, cyrus-imapd-utils-3.0.7-16.el8_2.1, cyrus-imapd-vzic-3.0.7-16.el8_2.1

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2021:3492
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2021:3546
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2021:3493
Not affected: 1 product
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-33582
  2. 2026-10-03 Alias added: GHSA-prxx-4m38-9m83

References

Patch 3

Advisory 4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences