CVE-2026-72693
Full vulnerability record from the local CVENow database.
Description
`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.
Severity
HIGH
CVSS score
7.8
(v3.1)
Vulnerability status
Awaiting Analysis
Source identifier
Published
2026-08-11 09:17:14.340000
Last modified
2026-11-02 11:17:32.133000
View original CVE JSON
{
"id": "CVE-2026-72693",
"sourceIdentifier": "[email protected]",
"published": "2026-08-11T09:17:14.340",
"lastModified": "2026-11-02T11:17:32.133",
"vulnStatus": "Awaiting Analysis",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "`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."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
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"product": "Red Hat Enterprise Linux 10",
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"packageName": "kbd",
"cpes": [
"cpe:/o:redhat:enterprise_linux:10.2"
],
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{
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"packageName": "kbd-main",
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{
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"packageName": "kbd",
"cpes": [
"cpe:/o:redhat:enterprise_linux:6"
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{
"vendor": "Red Hat",
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"packageName": "kbd",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7"
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{
"vendor": "Red Hat",
"product": "Red Hat OpenShift Container Platform 4",
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"packageName": "openshift/ose-rhel-coreos-8",
"cpes": [
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{
"vendor": "Red Hat",
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"cpes": [
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],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-08-11T17:44:26.656399Z",
"id": "CVE-2026-72693",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-284"
}
]
}
],
"references": [
{
"url": "https://access.redhat.com/errata/RHSA-2026:41136",
"source": "[email protected]"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:57597",
"source": "[email protected]"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:57610",
"source": "[email protected]"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:60440",
"source": "[email protected]"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:66357",
"source": "[email protected]"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:78951",
"source": "[email protected]"
},
{
"url": "https://access.redhat.com/security/cve/CVE-2026-72693",
"source": "[email protected]"
},
{
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2462115",
"source": "[email protected]"
}
]
}