CVE-2026-42006
4.3
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Open-Xchange GmbH | OX Dovecot Pro | 0 <= 3.0.5 | affected |
| Open-Xchange GmbH | OX Dovecot Pro | 0 <= 3.1.4 | affected |
| Open-Xchange GmbH | OX Dovecot Pro | 0 <= 2.4.3 | affected |
Weaknesses
- CWE-400: Uncontrolled Resource Consumption
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: none
- Automatable: no
- Technical Impact: partial
dovecot: Dovecot: Denial of Service via excessive IMAP bracing
Additional References
- https://access.redhat.com/security/cve/CVE-2026-42006
- https://bugzilla.redhat.com/show_bug.cgi?id=2476476
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42006.json
References
- https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json
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