CVE Catalog

CVE-2026-78422

HighCVSS 7.3
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.09%

1th percentile - higher than 1% of all known CVEs

Summary

In the zbus_polkit crate before 5.1.0, Subject::new_for_owner() encodes the uid as unsigned 32-bit, while the polkit interface expects signed 32-bit. This mismatch causes polkit to ignore the supplied UID and determine the owner itself via PID, leading to a TOCTOU race. A local attacker can exploit this to bypass polkit authorization and perform unauthorized actions.

Risk Assessment

A local attacker can bypass polkit authorization checks and perform actions without proper permissions, potentially leading to privilege escalation or integrity compromise.

Recommendation

Update zbus_polkit to version 5.1.0 or later, which includes the fix.

Related vulnerabilities

Original NVD description (English source)

Subject::new_for_owner() in the zbus_polkit crate encodes the uid entry of a unix-process polkit subject as an unsigned 32-bit integer (D-Bus type u), whereas the org.freedesktop.PolicyKit1.Authority interface specifies a signed 32-bit integer (D-Bus type i). Because of this type mismatch, polkit silently discards the caller-supplied UID and instead determines the subject's owner itself by looking up the PID in /proc, a lookup that is inherently subject to a time-of-check/time-of-use race. Consequently, an application that passes a UID obtained from a trustworthy source — for example SO_PEERCRED Unix socket peer credentials — in order to defend against PID reuse receives no protection, and the supplied UID has no effect on the authorization decision. A local unprivileged attacker who can cause an authorized process to terminate and then win the race to have their own process assigned the same PID can be authorized under the identity of the terminated process, bypassing the polkit authorization check and performing actions the attacker is not entitled to. This issue affects zbus_polkit before 5.1.0.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS