Bug 2456276 (CVE-2026-34078)

Summary: CVE-2026-34078 flatpak: Flatpak: Arbitrary code execution via crafted symlinks in sandbox-expose options
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Flatpak, a Linux application sandboxing and distribution framework. A malicious application could exploit this by using specially crafted symlinks within the sandbox-expose options of the Flatpak portal. This allows the application to access arbitrary host files and potentially achieve code execution on the host system, bypassing the intended security sandbox.
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Bug Depends On: 2456383, 2456384    
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Description OSIDB Bzimport 2026-04-07 22:01:32 UTC
Flatpak is a Linux application sandboxing and distribution framework. Prior to 1.16.4, the Flatpak portal accepts paths in the sandbox-expose options which can be app-controlled symlinks pointing at arbitrary paths. Flatpak run mounts the resolved host path in the sandbox. This gives apps access to all host files and can be used as a primitive to gain code execution in the host context. This vulnerability is fixed in 1.16.4.