RHSA-2026:41136
Vulnerability from csaf_redhat - Published: 2026-07-16 23:21 - Updated: 2026-08-13 22:42Summary
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
Severity
Moderate
Notes
Topic: An update for Red Hat Hardened Images RPMs is now available.
Details: This update includes the following RPMs:
kbd:
* kbd-2.10.0-2.hum1 (aarch64, x86_64)
* kbd-legacy-2.10.0-2.hum1 (noarch)
* kbd-misc-2.10.0-2.hum1 (noarch)
* kbd-2.10.0-2.hum1.src (src)
Terms of Use: This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.
`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.
7.8 (High)
Affected products
Fixed
4 products
| Product | Identifier | Version | Remediation |
|---|---|---|---|
| Unresolved product id: Red Hat Hardened Images:kbd-main@aarch64 | — |
Vendor Fix
fix
Workaround
|
|
| Unresolved product id: Red Hat Hardened Images:kbd-main@noarch | — |
Vendor Fix
fix
Workaround
|
|
| Unresolved product id: Red Hat Hardened Images:kbd-main@src | — |
Vendor Fix
fix
Workaround
|
|
| Unresolved product id: Red Hat Hardened Images:kbd-main@x86_64 | — |
Vendor Fix
fix
Workaround
|
Threats
Impact
Moderate
References
9 references
Acknowledgments
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"text": "This update includes the following RPMs:\n\nkbd:\n * kbd-2.10.0-2.hum1 (aarch64, x86_64)\n * kbd-legacy-2.10.0-2.hum1 (noarch)\n * kbd-misc-2.10.0-2.hum1 (noarch)\n * kbd-2.10.0-2.hum1.src (src)",
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"title": "Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update",
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"vulnerabilities": [
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"acknowledgments": [
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"summary": "This issue was discovered by Red Hat."
}
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"cve": "CVE-2026-72693",
"cwe": {
"id": "CWE-284",
"name": "Improper Access Control"
},
"discovery_date": "2026-04-26T18:17:20+00:00",
"ids": [
{
"system_name": "Red Hat Bugzilla ID",
"text": "2462115"
}
],
"notes": [
{
"category": "description",
"text": "`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.",
"title": "Vulnerability description"
},
{
"category": "summary",
"text": "kbd: Local privilege escalation in openvt via incorrect process owner verification allowing passwordless root login",
"title": "Vulnerability summary"
},
{
"category": "other",
"text": "A flaw was found in openvt (part of the kbd package) where incorrect process owner verification can allow a local unprivileged attacker to achieve passwordless root login. However, exploitation requires a non-default kbrequest/init configuration that explicitly invokes openvt -u, combined with a specific timing condition where TTY ownership has returned to root after logout while an unprivileged process still holds an open file descriptor to the TTY. This combination of prerequisites \u2014 a deliberately configured kbrequest/init setup and a narrow TTY-state race \u2014 is not present in standard Red Hat product deployments. For this reason, Red Hat rates the impact of this vulnerability as Moderate despite the high CVSS base score, which reflects only the technical worst-case impact and not the real-world exploitation constraints.",
"title": "Statement"
},
{
"category": "general",
"text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product\u0027s status, and are included for informational purposes to better understand the severity of this vulnerability.",
"title": "CVSS score applicability"
}
],
"product_status": {
"fixed": [
"Red Hat Hardened Images:kbd-main@aarch64",
"Red Hat Hardened Images:kbd-main@noarch",
"Red Hat Hardened Images:kbd-main@src",
"Red Hat Hardened Images:kbd-main@x86_64"
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"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2462115"
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{
"category": "external",
"summary": "https://nvd.nist.gov/vuln/detail/CVE-2026-72693",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72693"
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],
"release_date": "2026-08-11T06:58:59.200000+00:00",
"remediations": [
{
"category": "vendor_fix",
"date": "2026-07-16T23:21:09+00:00",
"details": "For details on how to apply this update, which includes the changes described in this advisory, refer to:\nhttps://images.redhat.com/",
"product_ids": [
"Red Hat Hardened Images:kbd-main@aarch64",
"Red Hat Hardened Images:kbd-main@noarch",
"Red Hat Hardened Images:kbd-main@src",
"Red Hat Hardened Images:kbd-main@x86_64"
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"restart_required": {
"category": "none"
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"url": "https://access.redhat.com/errata/RHSA-2026:41136"
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{
"category": "workaround",
"details": "To mitigate this issue, avoid using `openvt -u` in privileged `kbrequest`/init deployments. Instead, configure the keyboard request to initiate a standard authenticated login on the new virtual terminal, or disable the keyboard request binding entirely until a fix is available. Changes to `kbrequest` configurations may require a system restart or service reload to take effect.",
"product_ids": [
"Red Hat Hardened Images:kbd-main@aarch64",
"Red Hat Hardened Images:kbd-main@noarch",
"Red Hat Hardened Images:kbd-main@src",
"Red Hat Hardened Images:kbd-main@x86_64"
]
}
],
"scores": [
{
"cvss_v3": {
"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"
},
"products": [
"Red Hat Hardened Images:kbd-main@aarch64",
"Red Hat Hardened Images:kbd-main@noarch",
"Red Hat Hardened Images:kbd-main@src",
"Red Hat Hardened Images:kbd-main@x86_64"
]
}
],
"threats": [
{
"category": "impact",
"details": "Moderate"
}
],
"title": "kbd: Local privilege escalation in openvt via incorrect process owner verification allowing passwordless root login"
}
]
}
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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.
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.
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