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.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Open-Xchange GmbH OX Dovecot Pro
Default version status: unaffected
0 to ≤ 3.0.5affected0 to ≤ 3.1.4affected0 to ≤ 2.4.3affected
References
- https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json ↗
- 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 ↗
- https://access.redhat.com/errata/RHSA-2026:49513 ↗
- https://access.redhat.com/errata/RHSA-2026:42091 ↗
- https://access.redhat.com/errata/RHSA-2026:41988 ↗
- https://access.redhat.com/errata/RHSA-2026:46532 ↗
- https://access.redhat.com/errata/RHSA-2026:46380 ↗
- https://access.redhat.com/errata/RHSA-2026:46379 ↗
- https://access.redhat.com/errata/RHSA-2026:46381 ↗
- https://access.redhat.com/errata/RHSA-2026:44373 ↗
- https://access.redhat.com/errata/RHSA-2026:44357 ↗
- https://access.redhat.com/errata/RHSA-2026:44355 ↗
- https://access.redhat.com/errata/RHSA-2026:41905 ↗