Bug 2525530 (CVE-2026-40013)

Summary: CVE-2026-40013 dovecot: Dovecot: Denial of Service in ManageSieve service via crafted Sieve script
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in Dovecot. An authenticated attacker can submit a specially crafted Sieve script containing an extreme numeric literal to the ManageSieve service. This action triggers an out-of-bounds write during script compilation, leading to memory corruption and a crash of the ManageSieve process. This vulnerability results in a denial of service for script management and might also be leveraged for remote code execution.
 Story Points: ---
Clone Of: Environment:
Last Closed: 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: 2526672    
Bug Blocks:    

Description OSIDB Bzimport 2026-08-28 11:21:16 UTC 
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.