6.5

CVE-2026-40016: dovecot Uncontrolled Resource Consumption

CVSS: 6.5v3.1MediumAnalyzed
AliasesALPINE-CVE-2026-40016SUSE-SU-2026:4271-1UBUNTU-CVE-2026-40016
Published 12-05-2026Last modified 12-05-2026
Open JSON

Vulnerability summary

CVE-2026-40016 is a medium (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in dovecot. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 35.6% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.43%
0%100%
Low · +0.09 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 5
OPENSUSE-SU-2026:10766-1OPENSUSE-SU-2026:21109-1SUSE-SU-2026:22185-1SUSE-SU-2026:4139-1USN-8365-1

Timeline

  1. 12-05-2026
    PublishedVulnerability first disclosed.
  2. 12-05-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.43%

Chance of exploitation in the next 30 days

Percentile

36%

Versus all other CVEs

30-day change

+0.09 pp

From 0.34% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.43%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Alpine1 product
  • dovecot< 2.4.4-r0
Debian1 product
  • dovecot< 1:2.3.19.1+dfsg1-2.1+deb12u6 | < 1:2.4.1+dfsg1-6+deb13u6 | < 1:2.4.4+dfsg1-1
Dovecot1 product
Open-xchange1 product
Open-xchange gmbh1 product
Suse1 product
  • dovecot22&distro=SUSE Linux Enterprise Server LTSS Extended Security 12 SP5< 2.2.31-19.43.1
Ubuntu1 product
  • dovecotAll versions (No fix recorded) | < 1:2.3.16+dfsg1-3ubuntu2.9 | < 1:2.3.21+dfsg1-2ubuntu6.5 | < 1:2.4.1+dfsg1-5ubuntu4.2 | < 1:2.4.2+dfsg1-3ubuntu2.1

7 vendors · 7 products

References

10 links