CVE-2026-42006
An attacker can cause uncontrolled memory usage with excessive bracing over IMAP.
Does this matter?
Lower severity and a low EPSS score (0.62%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- EPSS
- 0.62% probability · 48th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-400, CWE-770
- Affected
- dovecot/dovecot · open-xchange/dovecot
- Source
- security@open-xchange.com
References
- https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.jsonIssue Tracking
- https://access.redhat.com/errata/RHSA-2026:41905
- https://access.redhat.com/errata/RHSA-2026:41988
- https://access.redhat.com/errata/RHSA-2026:42091
- https://access.redhat.com/errata/RHSA-2026:44355
- https://access.redhat.com/errata/RHSA-2026:44357
- https://access.redhat.com/errata/RHSA-2026:44373
- https://access.redhat.com/errata/RHSA-2026:46379
- https://access.redhat.com/errata/RHSA-2026:46380
- https://access.redhat.com/errata/RHSA-2026:46381
- https://access.redhat.com/errata/RHSA-2026:46532
- https://access.redhat.com/errata/RHSA-2026:49513
- 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.