Bug 2499603 (CVE-2026-12080)

Summary: CVE-2026-12080 qemu-kvm: qemu-guest-agent: Local privilege escalation via symlink attack in guest-ssh-add-authorized-keys
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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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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Bug Depends On: 2499616    
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Description OSIDB Bzimport 2026-07-13 08:48:30 UTC 
When qmp_guest_ssh_add_authorized_keys adds an SSH key for an existing local user, the agent (running as root) decides whether to create the user's .ssh directory with a symlink-following directory test, and then writes and chowns the authorized_keys file using a plain chown (not lchown). A local unprivileged user who owns their home directory can pre-stage their .ssh directory (or the authorized_keys file) as a symbolic link so that, when the host or operator triggers a key add for that user, the root agent follows the link and transfers ownership of an arbitrary root-owned file or directory to the unprivileged user, who can then rewrite it to obtain root.

Patch:
https://patchew.org/QEMU/20260709105707.91209-1-kkostiuk@redhat.com/