synced JUST NOW
01 Record

CVE-2026-42391

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be

HighPUBLISHEDCNA: OX
CNA base score7.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
View raw JSON

02 Description

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.44% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 38.7% of scored records. A rank, not a probability.
NVD base score
7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD analysis status
Deferred. NVD last modified this record on 2026-09-03.
Red Hat severity
Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-08-28 10:12Z2 MO AGO
Last updated
2026-08-28 15:54Z2 MO AGO
Reserved
2026-04-27
Assigning CNA
OX
Record state
PUBLISHED
Severity
High (CVSS 7.5)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
  • CWE-400Uncontrolled Resource ConsumptionClass
  • CWE-770Allocation of Resources Without Limits or ThrottlingBase
Data version
5.2
Document digest
b0945a24f9e0966c025c3b72b8a63aa44b6b8f54a1c6e6a9dd3f364cfe412104

05 Affected products

VendorProductVersionsPlatforms
Open-Xchange GmbHOX Dovecot Pro2.3.0 to < 2.3.22.2, 3.0.0 to < 3.0.7, 3.1.0 to < 3.1.6—
Open-Xchange GmbHOX Dovecot CE2.3.0 to < 2.4.5—

06 References

07 Fixed in

AlmaLinux 8

  • dovecot
    Fixed in 1:2.3.16-16.el8_10
  • dovecot-devel
    Fixed in 1:2.3.16-16.el8_10
  • dovecot-mysql
    Fixed in 1:2.3.16-16.el8_10
  • dovecot-pgsql
    Fixed in 1:2.3.16-16.el8_10
  • dovecot-pigeonhole
    Fixed in 1:2.3.16-16.el8_10

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 9

  • dovecot
    Fixed in 1:2.3.16-18.el9_8.8
  • dovecot-devel
    Fixed in 1:2.3.16-18.el9_8.8
  • dovecot-mysql
    Fixed in 1:2.3.16-18.el9_8.8
  • dovecot-pgsql
    Fixed in 1:2.3.16-18.el9_8.8
  • dovecot-pigeonhole
    Fixed in 1:2.3.16-18.el9_8.8

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 10

  • dovecot
    Fixed in 1:2.3.21-19.el10_2.8
  • dovecot-devel
    Fixed in 1:2.3.21-19.el10_2.8
  • dovecot-mysql
    Fixed in 1:2.3.21-19.el10_2.8
  • dovecot-pgsql
    Fixed in 1:2.3.21-19.el10_2.8
  • dovecot-pigeonhole
    Fixed in 1:2.3.21-19.el10_2.8

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 8

  • dovecot
    Fixed in 1:2.3.16-16.el8_10
  • dovecot-devel
    Fixed in 1:2.3.16-16.el8_10
  • dovecot-mysql
    Fixed in 1:2.3.16-16.el8_10
  • dovecot-pgsql
    Fixed in 1:2.3.16-16.el8_10
  • dovecot-pigeonhole
    Fixed in 1:2.3.16-16.el8_10

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 9

  • dovecot
    Fixed in 1:2.3.16-18.el9_8.8
  • dovecot-devel
    Fixed in 1:2.3.16-18.el9_8.8
  • dovecot-mysql
    Fixed in 1:2.3.16-18.el9_8.8
  • dovecot-pgsql
    Fixed in 1:2.3.16-18.el9_8.8
  • dovecot-pigeonhole
    Fixed in 1:2.3.16-18.el9_8.8

Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 10

  • dovecot
    Fixed in 1:2.3.21-19.el10_2.8
  • dovecot-devel
    Fixed in 1:2.3.21-19.el10_2.8
  • dovecot-mysql
    Fixed in 1:2.3.21-19.el10_2.8
  • dovecot-pgsql
    Fixed in 1:2.3.21-19.el10_2.8
  • dovecot-pigeonhole
    Fixed in 1:2.3.21-19.el10_2.8

Derived from AlmaLinux 10. Partial coverage: only packages taken from AlmaLinux 10 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Debian 12

  • dovecot
    No fix yet

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • dovecot
    Fixed in 1:2.4.1+dfsg1-6+deb13u7

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • dovecot
    Fixed in 1:2.4.5+dfsg1-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 16.04 LTS

  • dovecot
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • dovecot
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 20.04 LTS

  • dovecot
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 22.04 LTS

  • dovecot
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 24.04 LTS

  • dovecot
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 26.04 LTS

  • dovecot
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 14.04 LTS

  • dovecot
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.