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Response snapshot Nov 2, 2026, 12:31 UTC

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VulnerabilityCVE-2026-72693

`openvt -u` is intended to identify the owner of the current VT and then execute `login` as that user from a privileged context.

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").

At a glance

Exploited
Not known
Severity
7.8 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-72693 (opens a new tab)

What happened

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.

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Sources

  1. Primary source

    NVD CVE-2026-72693 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 2). `openvt -u` is intended to identify the owner of the current VT and then execute `login` as that user from a privileged context. (CVE-2026-72693). https://kevwire.com/record/CVE-2026-72693

MLA

"`openvt -u` is intended to identify the owner of the current VT and then execute `login` as that user from a privileged context. (CVE-2026-72693)." KEVWire, 2 Nov. 2026, kevwire.com/record/CVE-2026-72693.

Chicago

KEVWire. "`openvt -u` is intended to identify the owner of the current VT and then execute `login` as that user from a privileged context. (CVE-2026-72693)." Last modified November 2, 2026. https://kevwire.com/record/CVE-2026-72693.

Evidence summary (plain text)

`openvt -u` is intended to identify the owner of the current VT and then execute `login` as that user from a privileged context. (Aug 11, 2026).
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.
CVSS 7.8 (version 3.1; evidence as of Nov 2, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-72693).
Sources:
NVD CVE-2026-72693: https://nvd.nist.gov/vuln/detail/CVE-2026-72693
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-02T10:55:57.149Z&lastModEndDate=2026-11-02T12:30:57.130Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-02T10:20:57.768Z&lastModEndDate=2026-11-02T11:55:55.935Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-02T09:45:58.882Z&lastModEndDate=2026-11-02T11:20:55.391Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-72693.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 2, 2026, 12:30 UTC. Ingestion is not an independent editorial investigation.

NVD status: Awaiting Analysis. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail