Bug 2452180 (CVE-2026-27859)

Summary: CVE-2026-27859 dovecot: Dovecot: Denial of Service via excessive RFC 2231 MIME parameters
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: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in Dovecot. A remote attacker can exploit this vulnerability by sending a specially crafted mail message containing an excessive amount of RFC 2231 MIME parameters. This can cause the Local Mail Transfer Protocol (LMTP) process to consume large amounts of CPU time, leading to a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-03-27 09:02:26 UTC
A mail message containing excessive amount of RFC 2231 MIME parameters causes LMTP to use too much CPU. A suitably formatted mail message causes mail delivery process to consume large amounts of CPU time. Use MTA capabilities to limit RFC 2231 MIME parameters in mail messages, or upgrade to fixed version where the processing is limited. No publicly available exploits are known.