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TI-2026-30691 Aliases CVE-2026-42391GHSA-7597-pg24-8mv9

Uncontrolled resource consumption in Open-Xchange GmbH OX Dovecot Pro

Priority LOW 39CWE-400Published · 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: 6 fixed, 2 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-400.

Summary

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 terminated by the out-of-memory handling, which also terminates all other connections handled by the same process. This can cause degradation or denial of service for IMAP logins. Limit the number of connections handled by a single imap-login process. This has a performance impact though. Update to non-vulnerable version. No publicly available exploits are known.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00449 39th percentileScored 2026-11-07
Fix Partial OX Dovecot Pro (Open-Xchange GmbH): 2.3.22.2, 3.0.7, 3.1.6OX Dovecot CE (Open-Xchange GmbH): 2.4.5Red Hat: 3 advisoriesRed Hat: 6 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Open-Xchange GmbHOX Dovecot Pro2.3.0 to before 2.3.22.2; 3.0.0 to before 3.0.7; 3.1.0 to before 3.1.62.3.22.2, 3.0.7, 3.1.6Patch availableCNA
Open-Xchange GmbHOX Dovecot CE2.3.0 to before 2.4.52.4.5Patch availableCNA
  • OX Dovecot Pro VendorOpen-Xchange GmbH Affected 2.3.0 to before 2.3.22.2; 3.0.0 to before 3.0.7; 3.1.0 to before 3.1.6 Fixed in 2.3.22.2, 3.0.7, 3.1.6 Patch available CNA
  • OX Dovecot CE VendorOpen-Xchange GmbH Affected 2.3.0 to before 2.4.5 Fixed in 2.4.5 Patch available CNA

Remediation

  • Fix · CNA OX Dovecot Pro (Open-Xchange GmbH) Fixed in 2.3.22.2, 3.0.7, 3.1.6
  • Fix · CNA OX Dovecot CE (Open-Xchange GmbH) Fixed in 2.4.5

Red Hat 3 advisories

  • RHSA-2026:80825 Released 2026-10-12 · Red Hat rating Important
    dovecot security update
    • Red Hat Enterprise Linux AppStream (v. 9) dovecot-1:2.3.16-18.el9_8.8, dovecot-mysql-1:2.3.16-18.el9_8.8, dovecot-pgsql-1:2.3.16-18.el9_8.8 +1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) dovecot-1:2.3.16-18.el9_8.8, dovecot-devel-1:2.3.16-18.el9_8.8
  • RHSA-2026:79371 Released 2026-10-08 · Red Hat rating Important
    dovecot security update
    • Red Hat Enterprise Linux AppStream (v. 10) dovecot-1:2.3.21-19.el10_2.8, dovecot-mysql-1:2.3.21-19.el10_2.8, dovecot-pgsql-1:2.3.21-19.el10_2.8 +1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) dovecot-devel-1:2.3.21-19.el10_2.8
  • RHSA-2026:76763 Released 2026-10-06 · Red Hat rating Important
    dovecot security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 8) dovecot-1:2.3.16-16.el8_10, dovecot-mysql-1:2.3.16-16.el8_10, dovecot-pgsql-1:2.3.16-16.el8_10 +1
    • Red Hat Enterprise Linux CRB (v. 8) dovecot-1:2.3.16-16.el8_10, dovecot-devel-1:2.3.16-16.el8_10

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    Open-Xchange OX Dovecot CE, OX Dovecot Pro — documentation.open-xchange.com/dovecot/security/advisories/…

    25 records Highest priority Priority LOW 25 LOW

    Other records, highest priority first

    • TI-2026-30395 Use after free in Open-Xchange GmbH OX Dovecot ProPriority LOW 39
    • TI-2026-25987 Uncontrolled resource consumption in Open-Xchange GmbH OX Dovecot ProPriority LOW 39
    • TI-2026-22202 Uncontrolled resource consumption in Open-Xchange GmbH OX Dovecot ProPriority LOW 39
    Show all 25 records → Advisory →

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 yet
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:79371
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:76763
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:80825
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:76763
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:79371
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:80825

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42391
  2. 2026-10-03 Alias added: GHSA-7597-pg24-8mv9
  3. 2026-10-07 Fix available: RHSA-2026:76763 · Red Hat
  4. 2026-10-07 Fix available: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux CRB (v. 8) · Red Hat
  5. 2026-10-09 Fix available: RHSA-2026:79371 · Red Hat
  6. 2026-10-09 Fix available: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · Red Hat
  7. 2026-10-12 Fix available: RHSA-2026:80825 · Red Hat
  8. 2026-10-13 Fix available: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) · Red Hat

References

Advisory 1

  • TI-2024-04069 Improper check for unusual conditions in Mozilla Firefox CVSS 3.1HIGH 8.8
  • TI-2022-17394 OX App Suite through 7.10.6 allows SSRF because the anti-SSRF protection mechanism only… CVSS 3.1MEDIUM 5.3
  • TI-2022-17393 OX App Suite through 7.10.6 has Uncontrolled Resource Consumption via a large request… CVSS 3.1MEDIUM 5.3
  • TI-2022-17392 OX App Suite through 7.10.6 has Uncontrolled Resource Consumption via a large location… CVSS 3.1MEDIUM 5.3
  • TI-2022-17391 OX App Suite through 7.10.6 allows XSS via a malicious capability to the metrics or help… CVSS 3.1MEDIUM 6.1
  • TI-2022-17390 OX App Suite through 7.10.6 allows XSS via script code within a contact that has an e-mail address but lacks a name. CVSS 3.1MEDIUM 6.1
See all 317 →

Sources

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