TI-2026-25680 Aliases CVE-2026-33263 GHSA-9rqj-cvwq-v6qh

When mail_max_userip_connections is set (default 10) and reached, submission-login can…

LOW 21CWE-403Published 2026-08-28 · Updated 2026-08-28

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: None · None · Low
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.

Summary

When mail_max_userip_connections is set (default 10) and reached, submission-login can crash with epoll() panic caused by file descriptor handling issues. If running in high-security mode (default for community releases), only the new submission connection gets terminated. If running in high-performance mode (default for Pro releases), all connections handled by the submission-login process will be terminated. The crashes can cause failure for user to send a message, or it can cause duplicate messages to be sent. If TLS is not used (in the backend server processing the submission), duplicate deliveries cannot happen, because the crash can only happen at AUTH stage. Limit the number of connections handled by single submission-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 0.00554 46th 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: 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

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

Product	Status	Plan or fix
Red Hat Enterprise Linux 6	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 7	Affected	No 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

2026-10-02 Threatist record created from CVE-2026-33263
2026-10-03 Alias added: GHSA-9rqj-cvwq-v6qh
2026-10-07 Fix available: RHSA-2026:76763 · Red Hat
2026-10-07 Fix available: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux CRB (v. 8) · Red Hat
2026-10-09 Fix available: RHSA-2026:79371 · Red Hat
2026-10-09 Fix available: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · Red Hat
2026-10-12 Fix available: RHSA-2026:80825 · Red Hat
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

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