CVE-2026-48983
Full vulnerability record from the local CVENow database.
Description
pam_usb provides hardware authentication for Linux using ordinary removable media. In versions prior to 0.9.2, a symlink race condition exists in per-device and per-user pad directory creation. pam_usb uses a check-then-act pattern: it calls lstat() to test for existence and then calls mkdir() separately to create the directory. A local attacker can win the race between these calls by replacing the target path with a symlink to a directory they control. If successful, one-time pad files may be written to an attacker-controlled location, potentially exposing future pad values before use or disrupting authentication. This issue has been fixed in version 0.9.2.
Severity
MEDIUM
CVSS score
5.8
(v3.1)
Vulnerability status
Deferred
Source identifier
Published
2026-06-18 20:16:14.657000
Last modified
2026-10-26 11:10:00.157000
View original CVE JSON
{
"id": "CVE-2026-48983",
"sourceIdentifier": "[email protected]",
"published": "2026-06-18T20:16:14.657",
"lastModified": "2026-10-26T11:10:00.157",
"vulnStatus": "Deferred",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "pam_usb provides hardware authentication for Linux using ordinary removable media. In versions prior to 0.9.2, a symlink race condition exists in per-device and per-user pad directory creation. pam_usb uses a check-then-act pattern: it calls lstat() to test for existence and then calls mkdir() separately to create the directory. A local attacker can win the race between these calls by replacing the target path with a symlink to a directory they control. If successful, one-time pad files may be written to an attacker-controlled location, potentially exposing future pad values before use or disrupting authentication. This issue has been fixed in version 0.9.2."
},
{
"lang": "es",
"value": "pam_usb proporciona autenticación de hardware para Linux utilizando medios extraíbles ordinarios. En versiones anteriores a la 0.9.2, existe una condición de carrera de enlace simbólico en la creación de directorios de pad por dispositivo y por usuario. pam_usb utiliza un patrón de verificar y luego actuar: llama a lstat() para comprobar la existencia y luego llama a mkdir() por separado para crear el directorio. Un atacante local puede ganar la carrera entre estas llamadas reemplazando la ruta de destino con un enlace simbólico a un directorio que controla. Si tiene éxito, los archivos de pad de un solo uso pueden escribirse en una ubicación controlada por el atacante, exponiendo potencialmente valores de pad futuros antes de su uso o interrumpiendo la autenticación. Este problema ha sido corregido en la versión 0.9.2."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "mcdope",
"product": "pam_usb",
"versions": [
{
"version": "< 0.9.2",
"status": "affected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L",
"baseScore": 5.8,
"baseSeverity": "MEDIUM",
"attackVector": "LOCAL",
"attackComplexity": "HIGH",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "LOW",
"availabilityImpact": "LOW"
},
"exploitabilityScore": 1.0,
"impactScore": 4.7
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-06-22T12:41:19.864255Z",
"id": "CVE-2026-48983",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-367"
}
]
}
],
"references": [
{
"url": "https://github.com/mcdope/pam_usb/releases/tag/0.9.2",
"source": "[email protected]"
},
{
"url": "https://github.com/mcdope/pam_usb/security/advisories/GHSA-4j8q-67fq-3xc3",
"source": "[email protected]"
}
]
}