Bug 2532613 (CVE-2026-90616)

Summary: CVE-2026-90616 flatpak: Flatpak: Arbitrary code execution via missing symlink protection
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
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Hardware: All   
OS: Linux   
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A flaw was found in Flatpak. A malicious sandboxed application can exploit missing symlink protection during the creation and bind-mounting of app data directories. By manipulating attacker-controlled path components, a malicious symlink can redirect these directories to arbitrary locations on the host system. This allows the sandboxed application to gain arbitrary read and write access to host files, which can be escalated to arbitrary code execution on the host.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2532950    
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Description OSIDB Bzimport 2026-09-12 20:21:16 UTC 
In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnerability than CVE-2026-76925. Flatpak creates a few app data directories (e.g., /var/cache, /var/data, /var/config, and /var/tmp) in every sandbox on every app launch where, in some cases, components of the path are attacker-controlled. Missing symlink protection can redirect the directories. Some of these directories are bind-mounted by Flatpak by passing the path (e.g., /home/user/.var/app/APP_ID/cache/tmp), which contains attacker-controlled directories (tmp) to bwrap --bind SRC DST. bwrap passes the path on to the kernel, which then follows symlinks. A malicious symlink can point to arbitrary locations on the host and it will become mounted inside the sandbox.