Improper Access Control Affecting rhcos package, versions *


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.11% (2nd percentile)

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  • Snyk IDSNYK-RHEL7-RHCOS-18614558
  • published11 Aug 2026
  • disclosed11 Aug 2026

Introduced: 11 Aug 2026

NewCVE-2026-72693  (opens in a new tab)
CWE-284  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:7 rhcos.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rhcos package and not the rhcos package as distributed by RHEL. See How to fix? for RHEL:7 relevant fixed versions and status.

openvt -u is intended to identify the owner of the current VT and then execute login as that user from a privileged context. In the documented kbrequest/init usage, the ownership test in authenticate_user() relies on stat("/proc/<pid>/fd/0"). stat() on /proc/<pid>/fd/0 follows the symlink to the underlying TTY device node. As a result, buf.st_uid reflects the owner of the TTY node rather than the owner of the process holding the file descriptor. If the TTY owner returns to root or the getty owner after logout while an unprivileged process still has fd 0 attached to that TTY, the check can incorrectly treat that process as belonging to the privileged console owner. Once that check succeeds, the -u path executes a passwordless login as the selected user. In the documented kbrequest/init deployment using openvt -us, this can result in passwordless login -f root on the spawned VT. This report establishes that privilege escalation path for that documented deployment; it does not claim equivalent reachability for deployments that do not use openvt -u from a privileged kbrequest/init path.

CVSS Base Scores

version 3.1