CVE-2026-42006 — Open-Xchange GmbH / OX Dovecot Pro

Description (CNA)

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 (CNA)

Vendor / product	Versions
Open-Xchange GmbH / OX Dovecot Pro	affected 0 through 3.0.5; affected 0 through 3.1.4; affected 0 through 2.4.3

CWE

CWE-400

References

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in Dovecot. A remote attacker can exploit this vulnerability by sending excessive open braces over the Internet Message Access Protocol (IMAP), leading to uncontrolled memory usage. This can cause the affected system to consume memory up to its configured limit, resulting in a Denial of Service (DoS).