---
id: CVE-2026-72693
title: >-
  `openvt -u` is intended to identify the owner of the current VT and then
  execute `login` as that user from a privileged context
summary: >-
  `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…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-284
vendor: Red Hat
product: kbd
affected:
  - kbd (all versions)
  - kbd (all versions)
  - rhcos (all versions)
  - rhcos (all versions)
  - kbd-main (all versions)
  - kbd
  - kbd (all versions)
  - kbd (all versions)
  - openshift/ose-rhel-coreos-9 (all versions)
published: '2026-08-11'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T12:17:53.320'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72693'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:41136'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:57597'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:57610'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:60440'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:66357'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-72693'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2462115'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72693.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-72693'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72693'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-08-11T17:44:26.656399Z'
epss: 0.00157
epssPercentile: 0.04102
ingestedAt: '2026-09-15T12:36:50.169Z'
patched:
  - openshift_container_platform 4.22
  - enterprise_linux_baseos_v_10
  - enterprise_linux_baseos_v_9
  - hardened_images
---

## Overview

`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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:60440** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.22 · released 2026-09-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:60440)
- **RHSA-2026:66357** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.22 · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:66357)
- **RHSA-2026:57597** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-08-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:57597)
- **RHSA-2026:57610** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-08-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:57610)
- **RHSA-2026:41136** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-07-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:41136)
- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4 · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72693.json)