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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-40016

25
FAUCET Score

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.

First published: May 12, 2026Last modified: May 12, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 2.4.4CPE matchmatch criteria
cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*
< 3.1.5CPE matchmatch criteria
cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
1.6
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.34%
Probability of exploitation in next 30 days
EPSS Percentile
26.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0034 is in the 35th percentile among its peer group of 21,957 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

ubuntupatch availablevia ubuntu_usn
Product: dovecot (jammy)Fixed in: 1:2.3.16+dfsg1-3ubuntu2.9
ubuntupatch availablevia ubuntu_usn
Product: dovecot (noble)Fixed in: 1:2.3.21+dfsg1-2ubuntu6.5
ubuntupatch availablevia ubuntu_usn
Product: dovecot (questing)Fixed in: 1:2.4.1+dfsg1-5ubuntu4.2
ubuntupatch availablevia ubuntu_usn
Product: dovecot (resolute)Fixed in: 1:2.4.2+dfsg1-3ubuntu2.1

Vendor Advisories (1)

ubuntuUSN-8365-1

Dovecot vulnerabilities

Jun 2, 2026

References

documentation.open-xchange.com / dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json
Vendor Advisory