TI-2026-28857 Aliases CVE-2026-40014 GHSA-r364-r477-7mhc

Uncontrolled resource consumption in Open-Xchange GmbH OX Dovecot Pro

LOW 29CWE-400Published 2026-08-28 · Updated 2026-08-28

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 5 without a fix

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

Summary

An attacker that can send mail to a user can craft a message header that makes the IMAP THREAD command consume CPU disproportionate to the size of the message. When a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. 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 0.00334 26th 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: 5 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

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

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Open-Xchange GmbH	OX Dovecot Pro	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	2.3.22.2, 3.0.7, 3.1.6	Patch available	CNA
Open-Xchange GmbH	OX Dovecot CE	2.3.0 to before 2.4.5	2.4.5	Patch available	CNA

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

Fixed in the same release

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

Advisory · 2026-08-28
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-2026-30691 Uncontrolled resource consumption in Open-Xchange GmbH OX Dovecot ProPriority LOW 39
- 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
Show all 25 records → Advisory →

Vendor assessments

Red Hat

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

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 6	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 7	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 8	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 9	Affected	No fix yet: Fix deferred

Timeline

2026-10-02 Threatist record created from CVE-2026-40014
2026-10-03 Alias added: GHSA-r364-r477-7mhc

References

Advisory 1

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json

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