FKIE_CVE-2026-72693
Vulnerability from fkie_nvd - Published: 2026-08-11 09:17 - Updated: 2026-09-15 12:17
Severity
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/<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.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:10.2"
],
"defaultStatus": "affected",
"packageName": "kbd",
"product": "Red Hat Enterprise Linux 10",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "0:2.6.4-8.el10_2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::baseos"
],
"defaultStatus": "affected",
"packageName": "kbd",
"product": "Red Hat Enterprise Linux 9",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "0:2.4.0-12.el9_8",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4.22::el9"
],
"defaultStatus": "affected",
"packageName": "rhcos",
"product": "Red Hat OpenShift Container Platform 4.22",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "4.22.9.8.202608251819-0",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4.22::el9"
],
"defaultStatus": "affected",
"packageName": "rhcos",
"product": "Red Hat OpenShift Container Platform 4.22",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "4.22.9.8.202609081748-0",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:hummingbird:1"
],
"defaultStatus": "affected",
"packageName": "kbd-main",
"product": "Red Hat Hardened Images",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "2.10.0-2.hum1",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:6"
],
"defaultStatus": "unknown",
"packageName": "kbd",
"product": "Red Hat Enterprise Linux 6",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7"
],
"defaultStatus": "affected",
"packageName": "kbd",
"product": "Red Hat Enterprise Linux 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8"
],
"defaultStatus": "affected",
"packageName": "kbd",
"product": "Red Hat Enterprise Linux 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4"
],
"defaultStatus": "affected",
"packageName": "openshift/ose-rhel-coreos-9",
"product": "Red Hat OpenShift Container Platform 4",
"vendor": "Red Hat"
}
],
"source": "secalert@redhat.com"
}
],
"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/\u003cpid\u003e/fd/0\")`. `stat()` on `/proc/\u003cpid\u003e/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."
}
],
"id": "CVE-2026-72693",
"lastModified": "2026-09-15T12:17:53.320",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "secalert@redhat.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-72693",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-11T17:44:26.656399Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-08-11T09:17:14.340",
"references": [
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:41136"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:57597"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:57610"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:60440"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:66357"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/security/cve/CVE-2026-72693"
},
{
"source": "secalert@redhat.com",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2462115"
}
],
"sourceIdentifier": "secalert@redhat.com",
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-284"
}
],
"source": "secalert@redhat.com",
"type": "Secondary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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