Bug 2526672

Summary: CVE-2026-40013 dovecot: Dovecot: Denial of Service in ManageSieve service via crafted Sieve script [fedora-all]
Product: [Fedora] Fedora Reporter: Vladimir Vasilev <vvasilev>
Component: dovecotAssignee: Michal Hlavinka <mhlavink>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: anon.amish, bennie.joubert, mhlavink
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["9f0d7519-b693-454b-bc4b-2515f7c46228"]}
Fixed In Version: dovecot-2.4.5-1.fc45 dovecot-2.4.5-1.fc43 dovecot-2.4.5-1.fc44 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-09-19 00:16:09 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2525530    

Description Vladimir Vasilev 2026-09-01 07:25:05 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

An attacker that has valid credentials can submit a Sieve script containing an extreme numeric literal, which causes an out-of-bounds write when the ManageSieve service compiles the script. This causes memory corruption and an observed crash of the ManageSieve process, resulting in denial of service for script management. This might be able to be used for remote code execution. Disable the ManageSieve service if users do not need remote Sieve script management. Update to non-vulnerable version. No publicly available exploits are known.

Comment 1 Fedora Update System 2026-09-10 05:35:42 UTC
FEDORA-2026-e8a6485109 (dovecot-2.4.5-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-e8a6485109

Comment 2 Fedora Update System 2026-09-11 01:34:28 UTC
FEDORA-2026-8b8efbd2b8 has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-8b8efbd2b8`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-8b8efbd2b8

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 3 Fedora Update System 2026-09-11 02:07:17 UTC
FEDORA-2026-e8a6485109 has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-e8a6485109`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-e8a6485109

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 4 Fedora Update System 2026-09-11 02:27:12 UTC
FEDORA-2026-2e6b786570 has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-2e6b786570`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-2e6b786570

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 5 Fedora Update System 2026-09-19 00:16:09 UTC
FEDORA-2026-8b8efbd2b8 (dovecot-2.4.5-1.fc45) has been pushed to the Fedora 45 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 6 Fedora Update System 2026-09-19 00:57:20 UTC
FEDORA-2026-e8a6485109 (dovecot-2.4.5-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 7 Fedora Update System 2026-09-19 01:13:34 UTC
FEDORA-2026-2e6b786570 (dovecot-2.4.5-1.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.