CVE-2026-16552: systemdtmpfiles Symlink Spoofing (Integrity)
CVE-2026-16552 Published on July 22, 2026
Systemd: systemd-tmpfiles symlink-redirected arbitrary file overwrite via a chase_safe root-to-unprivileged ownership transition bypass
A flaw was found in systemd-tmpfiles. When processing a tmpfiles.d configuration entry that writes to a file, systemd-tmpfiles can follow a symbolic link placed by an unprivileged local user, and an existing safety check does not detect this specific case because it always treats transitions away from the root user as safe. On systems where a tmpfiles.d configuration targets a path an unprivileged user can influence, this could allow that user to redirect a privileged systemd-tmpfiles write to a file of their choosing, though the content written remains determined by the existing configuration rather than by the unprivileged user. The highest threat from this vulnerability is to integrity.
Vulnerability Analysis
CVE-2026-16552 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, a high impact on integrity and availability.
Timeline
Reported to Red Hat.
Made public. 47 days later.
Weakness Type
What is an insecure temporary file Vulnerability?
The software attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
CVE-2026-16552 has been classified to as an insecure temporary file vulnerability or weakness.
Products Associated with CVE-2026-16552
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