CVE-2026-42006
MEDIUM severity · CVSS 4.3 · Uncontrolled resource consumption
4.3CVSS MEDIUM
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.
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
Confidentiality impactNone
Integrity impactNone
Availability impactLow
Exploit probability (EPSS)1%
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Affected products we track (1)
Recommendation
Apply the vendor fix in your normal patch cycle. Open any affected product above for its exact safe version.
Additional information
- NVD record
- https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json
- https://access.redhat.com/errata/RHSA-2026:41905
- 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