CVE-2026-42006: Uncontrolled Resource Consumption in Open-Xchange GmbH OX Dovecot Pro
An attacker can cause uncontrolled memory usage with excessive bracing over IMAP. The fix in CVE-2026-27857 was incomplete, only blocking one way of doing this, so there was still another way left open. In particular, the fix was for closing braces, but you could still use open braces to bypass the limit. Using excessive bracing, attacker can cause memory usage up to configured memory limit. Install fixed version, or configure vsz_limit for imap process to low value. No publicly available exploits are known.
AI Analysis
Technical Summary
This vulnerability involves uncontrolled resource consumption in OX Dovecot Pro through excessive bracing in IMAP commands. The prior fix addressed only closing braces, allowing attackers to bypass limits using open braces. By sending IMAP commands with excessive open braces, an attacker can cause the server's memory usage to spike up to the configured memory limit. The vulnerability does not affect confidentiality or integrity but impacts availability due to potential resource exhaustion. No known public exploits exist. Mitigation options include applying a fixed software version or setting a low vsz_limit for the IMAP process to restrict memory usage.
Potential Impact
The vulnerability allows an attacker with at least low privileges (PR:L) to cause a denial of service condition by exhausting memory resources on the affected server. There is no impact on confidentiality or integrity. The attack vector is network-based with no user interaction required. The overall impact is limited to availability degradation due to uncontrolled memory consumption.
Mitigation Recommendations
A fixed version of OX Dovecot Pro should be installed once available to fully address this vulnerability. Until then, configuring the vsz_limit parameter for the IMAP process to a low value is recommended to limit memory usage and mitigate the risk. Since no official patch or advisory details are provided, users should monitor Open-Xchange GmbH communications for an official fix.
CVE-2026-42006: Uncontrolled Resource Consumption in Open-Xchange GmbH OX Dovecot Pro
Description
An attacker can cause uncontrolled memory usage with excessive bracing over IMAP. The fix in CVE-2026-27857 was incomplete, only blocking one way of doing this, so there was still another way left open. In particular, the fix was for closing braces, but you could still use open braces to bypass the limit. Using excessive bracing, attacker can cause memory usage up to configured memory limit. Install fixed version, or configure vsz_limit for imap process to low value. No publicly available exploits are known.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves uncontrolled resource consumption in OX Dovecot Pro through excessive bracing in IMAP commands. The prior fix addressed only closing braces, allowing attackers to bypass limits using open braces. By sending IMAP commands with excessive open braces, an attacker can cause the server's memory usage to spike up to the configured memory limit. The vulnerability does not affect confidentiality or integrity but impacts availability due to potential resource exhaustion. No known public exploits exist. Mitigation options include applying a fixed software version or setting a low vsz_limit for the IMAP process to restrict memory usage.
Potential Impact
The vulnerability allows an attacker with at least low privileges (PR:L) to cause a denial of service condition by exhausting memory resources on the affected server. There is no impact on confidentiality or integrity. The attack vector is network-based with no user interaction required. The overall impact is limited to availability degradation due to uncontrolled memory consumption.
Mitigation Recommendations
A fixed version of OX Dovecot Pro should be installed once available to fully address this vulnerability. Until then, configuring the vsz_limit parameter for the IMAP process to a low value is recommended to limit memory usage and mitigate the risk. Since no official patch or advisory details are provided, users should monitor Open-Xchange GmbH communications for an official fix.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- OX
- Date Reserved
- 2026-04-23T11:15:21.199Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a0333e5cbff5d8610ef1d37
Added to database: 5/12/2026, 2:06:29 PM
Last enriched: 5/12/2026, 2:22:01 PM
Last updated: 5/12/2026, 6:28:12 PM
Views: 8
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