Bug 2451779 (CVE-2026-3114)

Summary: CVE-2026-3114 Mattermost: Mattermost: Denial of Service via crafted zip archives
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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Hardware: All   
OS: Linux   
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A flaw was found in Mattermost. Authenticated users with file upload permissions can exploit this vulnerability by uploading specially crafted zip archives, known as "zip bombs," which contain highly compressed entries. When these archives are decompressed, they exhaust server memory, leading to a denial of service (DoS) for the application.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-03-26 17:02:06 UTC
Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to validate decompressed archive entry sizes during file extraction which allows authenticated users with file upload permissions to cause a denial of service via crafted zip archives containing highly compressed entries (zip bombs) that exhaust server memory.. Mattermost Advisory ID: MMSA-2026-00598