Bug 2525583 (CVE-2026-42007)

Summary: CVE-2026-42007 dovecot: Dovecot: Arbitrary Code Execution via Sieve editheader use-after-free
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Dovecot. An authenticated attacker can use a Sieve script with the `editheader` extension to trigger a use-after-free vulnerability in the mail editing code. This can lead to memory corruption, potentially crashing the mail delivery process and allowing for arbitrary code execution in the context of that process.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2526683    
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Description OSIDB Bzimport 2026-08-28 11:24:15 UTC 
An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing code, and to write memory contents beyond the intended buffer into the delivered mail. This causes memory leak and opportunity to do memory corruption during mail delivery, which can crash the delivery process and may allow execution of arbitrary code in the context of that process. Disable the Sieve editheader extension. Update to non-vulnerable version. No publicly available exploits are known.