← Vulnerability feed

Vulnerability record · CVE-2026-78422 · published 31 August 2026

CVE-2026-78422: TOCTOU race condition vulnerability

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.

7.3 CVSS 4.0 High EPSS 0.13% · top 98.1% CWE-367 · TOCTOU race conditionCWE-686 · CWE-686 Awaiting Analysis
7.3CVSS 4.0 base score
0.13%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
1 Sep 2026Last modified by NVD

Description

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.

CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

LinkTags
https://bugzilla.suse.com/show_bug.cgi?id=1277659
https://github.com/z-galaxy/zbus_polkit/pull/101

Track CVE-2026-78422 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

5.1CVE-2015-3246libuser userhelper direct /etc/passwd write race conditionlibuser before 0.56.13-8 and 0.60 before 0.60-7, as used by the userhelper program in the usermode package, modifies /etc/passwd directly instead of …KEVEPSS 8.8%analysed7.8CVE-2025-38352Linux kernel POSIX CPU timer TOCTOU race enables local privilege escalationA time-of-check to time-of-use race exists in the Linux kernel between handle_posix_cpu_timers() and posix_cpu_timer_del(). When an exiting non-autor…KEVEPSS 1.3%analysed8.2CVE-2025-22224VMware ESXi and Workstation TOCTOU race leads to out-of-bounds writeVMware ESXi, Workstation, and related products contain a TOCTOU race condition that results in an out-of-bounds write. An attacker with local adminis…KEVEPSS 1.6%analysed7.0CVE-2024-30088Windows Kernel TOCTOU race condition privilege escalationCVE-2024-30088 is a time-of-check time-of-use (TOCTOU) race condition in the Windows kernel that allows a local user to elevate privileges. It affect…KEVEPSS 68%analysed7.0CVE-2022-48618Apple OS Pointer Authentication Bypass via TOCTOU Race ConditionA time-of-check time-of-use race condition in Apple's pointer authentication implementation allows an attacker who already holds arbitrary read and w…KEVEPSS 0.49%analysed8.8CVE-2023-35311Microsoft Outlook security feature bypass via TOCTOU race conditionCVE-2023-35311 is a security feature bypass in Microsoft Outlook caused by a time-of-check time-of-use (TOCTOU) race condition (CWE-367). It affects …KEVEPSS 16%analysed

Source: NIST National Vulnerability Database (record CVE-2026-78422), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.