CVE-2026-42006

medium

Published 2026-05-12 · Modified 2026-05-18

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CVSS v3

4.3

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS v4 NEW

—

not yet in upstream

VIR risk

4.3

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.

Predictions

Exploit likelihood

53%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

OS	Version	Status	Fixed in
debian	bookworm	affected
debian	bullseye	affected
debian	forky	fixed	`1:2.4.4+dfsg1-1`
debian	sid	fixed	`1:2.4.4+dfsg1-1`
debian	trixie	affected
sles		affected

Application impact

Vendor	Product	Versions	Fixed
dovecot	dovecot	`{"endExcluding":"2.4.4"}`	`2.4.4`
open-xchange	dovecot	`{"endExcluding":"3.1.5"}`	`3.1.5`

References

CWEs

CWE-400

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.