Bug 2561617

Summary: CVE-2026-110249 thunderbird: Denial-of-service in the Exchange email component [fedora-all]
Product: [Fedora] Fedora Reporter: Vipul Nair <vinair>
Component: thunderbirdAssignee: Jan Horak <jhorak>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: low    
Version: rawhideCC: jhorak, klaas, rstrode, suraj.ghimire7
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["51f64bff-4f97-4345-8b41-3155ac82ef53"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:    
Bug Blocks: 2550754    

Description Vipul Nair 2026-10-27 10:17:16 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.

A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response containing an element with enough attributes to keep Thunderbird's main thread CPU-bound for seconds to hours. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.5.