CVE-2026-78422
Description
A flaw was found in zbus_polkit. The Subject::new_for_owner() function incorrectly encodes the user ID (UID) as an unsigned 32-bit integer instead of a signed 32-bit integer when communicating with the PolicyKit (polkit) authorization framework. This type mismatch causes polkit to disregard the provided UID and instead determine the subject's owner by looking up the process ID (PID) in /proc. A local unprivileged attacker can exploit a time-of-check/time-of-use (TOCTOU) race condition by terminating an authorized process and then reusing its PID, thereby bypassing polkit authorization and gaining unauthorized privileges.
Statement
Red Hat products are not affected by this vulnerability as they do not ship the zbus_polkit crate. Community packages in Fedora and EPEL are affected.
Mitigation
Upgrade zbus_polkit to version 5.1.0 or later.
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The attacker can gain access to otherwise unauthorized resources.
Integrity,Other
Technical Impact: Modify Application Data; Modify Files or Directories; Modify Memory; Other
Race conditions such as this kind may be employed to gain read or write access to resources which are not normally readable or writable by the user in question.
Integrity,Other
Technical Impact: Other
The resource in question, or other resources (through the corrupted one), may be changed in undesirable ways by a malicious user.
Non-Repudiation
Technical Impact: Hide Activities
If a file or other resource is written in this method, as opposed to in a valid way, logging of the activity may not occur.
Non-Repudiation,Other
Technical Impact: Other
In some cases it may be possible to delete files a malicious user might not otherwise have access to, such as log files.
Other
Technical Impact: Unexpected State
The product may perform invalid actions when the resource is in an unexpected state.
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