CVE-2026-40016
MEDIUM
MEDIUM
Priority: 0.02
BB Relevance:
63/100
Published: 2026-05-12
Modified: 2026-10-26
First seen: 2026-10-29
Status: active
Attack Surface
Network
Low Complexity
No Interaction
CVSS Vector Breakdown
AV:
Network
AC:
Low
PR:
Low
UI:
None
S:
Unchanged
C:
None
I:
None
A:
High
Description
Attacker can upload a malicious Sieve script over ManageSieve service (or locally) to bypass configured CPU time limits for Sieve up to 130 times of the configured limit. Attacker can use this to degrade server performance and bypass configured CPU time limits for Sieve scripts. Install fixed version, or alternatively prevent direct access to Sieve scripts via ManageSieve or local access. No publicly available exploits are known.
Weakness Classification (1)
Affected Software (2)
| Vendor | Product | Version |
|---|---|---|
| dovecot | dovecot | < 2.4.4 |
| open-xchange | dovecot | < 3.1.5 |
References & Advisories (1)
Vendor Advisory