Bug 2525557 (CVE-2026-27852)

Summary: CVE-2026-27852 dovecot: Dovecot: Denial of service via crafted email headers
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
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in dovecot. A remote attacker can craft a malicious email with an excessive number of email addresses or MIME parameters in its headers. When a user attempts to read this message over IMAP, the parsing process consumes an inordinate amount of memory, leading to the termination of the process. This can result in a denial of service for the affected user.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2526664, 2526665, 2526666    
Bug Blocks:    

Description OSIDB Bzimport 2026-08-28 11:22:45 UTC 
An attacker that can send mail to a user can craft a message whose headers contain a very large number of email addresses or MIME parameters, which causes excessive memory usage when the message is later parsed. The message is still delivered, but reading it over IMAP can exhaust the memory limit of the process and terminate it, causing denial of service for the affected user. Update to non-vulnerable version. No publicly available exploits are known.