RUSTSEC-2026-0278: `zbus_polkit`: authorization bypass via PID reuse

What to do

1. See which version you have: cargo tree -i zbus_polkit (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p zbus_polkit. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example zbus_polkit = "5.1.0") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

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.

References

• Package: crates.io/crates/zbus_polkit
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0278.html
• Web: github.com/z-galaxy/zbus_polkit/pull/101
• Web: bugzilla.suse.com/show_bug.cgi?id=1277659

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.