CVE-2026-40016

Publication date 12 May 2026

Last updated 5 June 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

5.3 · Medium

Score breakdown

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.

Status

Package Ubuntu Release Status
dovecot 26.04 LTS resolute
Fixed 1:2.4.2+dfsg1-3ubuntu2.1
25.10 questing
Fixed 1:2.4.1+dfsg1-5ubuntu4.2
24.04 LTS noble
Fixed 1:2.3.21+dfsg1-2ubuntu6.5
22.04 LTS jammy
Fixed 1:2.3.16+dfsg1-3ubuntu2.9
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty
Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
dovecot

Severity score breakdown

CVSS version: CVSS v3.0

Base score 5.3 · Medium

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

References

Related Ubuntu Security Notices (USN)

Other references

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