CVE-2025-38632
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: pinmux: fix race causing mux_owner NULL with active mux_usecount commit 5a3e85c3c397 ("pinmux: Use sequential access to access desc->pinmux data") tried to address the issue when two client of the same gpio calls pinctrl_select_state() for the same functionality, was resulting in NULL pointer issue while accessing desc->mux_owner. However, issue was not completely fixed due to the way it was handled and it can still result in the same NULL pointer. The issue occurs due to the following interleaving: cpu0 (process A) cpu1 (process B) pin_request() { pin_free() { mutex_lock() desc->mux_usecount--; //becomes 0 .. mutex_unlock() mutex_lock(desc->mux) desc->mux_usecount++; // becomes 1 desc->mux_owner = owner; mutex_unlock(desc->mux) mutex_lock(desc->mux) desc->mux_owner = NULL; mutex_unlock(desc->mux) This sequence leads to a state where the pin appears to be in use (`mux_usecount == 1`) but has no owner (`mux_owner == NULL`), which can cause NULL pointer on next pin_request on the same pin. Ensure that updates to mux_usecount and mux_owner are performed atomically under the same lock. Only clear mux_owner when mux_usecount reaches zero and no new owner has been assigned.
Severity
MEDIUM
CVSS score
4.7
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-08-22 16:15:37.033000
Last modified
2026-10-30 13:18:06.903000
View original CVE JSON
{
"id": "CVE-2025-38632",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2025-08-22T16:15:37.033",
"lastModified": "2026-10-30T13:18:06.903",
"vulnStatus": "Modified",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\npinmux: fix race causing mux_owner NULL with active mux_usecount\n\ncommit 5a3e85c3c397 (\"pinmux: Use sequential access to access\ndesc->pinmux data\") tried to address the issue when two client of the\nsame gpio calls pinctrl_select_state() for the same functionality, was\nresulting in NULL pointer issue while accessing desc->mux_owner.\nHowever, issue was not completely fixed due to the way it was handled\nand it can still result in the same NULL pointer.\n\nThe issue occurs due to the following interleaving:\n\n cpu0 (process A) cpu1 (process B)\n\n pin_request() { pin_free() {\n\n mutex_lock()\n desc->mux_usecount--; //becomes 0\n ..\n mutex_unlock()\n\n mutex_lock(desc->mux)\n desc->mux_usecount++; // becomes 1\n desc->mux_owner = owner;\n mutex_unlock(desc->mux)\n\n mutex_lock(desc->mux)\n desc->mux_owner = NULL;\n mutex_unlock(desc->mux)\n\nThis sequence leads to a state where the pin appears to be in use\n(`mux_usecount == 1`) but has no owner (`mux_owner == NULL`), which can\ncause NULL pointer on next pin_request on the same pin.\n\nEnsure that updates to mux_usecount and mux_owner are performed\natomically under the same lock. Only clear mux_owner when mux_usecount\nreaches zero and no new owner has been assigned."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: pinmux: corrección de la carrera que causaba que mux_owner fuera nulo con el commit 5a3e85c3c397 de mux_usecount activa (\"pinmux: Usar acceso secuencial para acceder a los datos de desc->pinmux\"). Se intentó solucionar el problema cuando dos clientes del mismo GPIO llamaban a pinctrl_select_state() para la misma funcionalidad, lo que provocaba un problema de puntero nulo al acceder a desc->mux_owner. Sin embargo, el problema no se solucionó por completo debido a la forma en que se gestionó y aún puede resultar en el mismo puntero nulo. El problema se produce debido a la siguiente intercalación: cpu0 (proceso A) cpu1 (proceso B) pin_request() { pin_free() { mutex_lock() desc->mux_usecount--; //se convierte en 0 .. mutex_unlock() mutex_lock(desc->mux) desc->mux_usecount++; // se convierte en 1 desc->mux_owner = owner; mutex_unlock(desc->mux) mutex_lock(desc->mux) desc->mux_owner = NULL; mutex_unlock(desc->mux) Esta secuencia lleva a un estado donde el pin parece estar en uso (`mux_usecount == 1`) pero no tiene propietario (`mux_owner == NULL`), lo que puede generar un puntero nulo en la siguiente solicitud de pin en el mismo pin. Asegúrese de que las actualizaciones de mux_usecount y mux_owner se realicen automáticamente bajo el mismo bloqueo. Solo borre mux_owner cuando mux_usecount llegue a cero y no se haya asignado un nuevo propietario."
}
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"source": "[email protected]",
"type": "Primary",
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"baseScore": 4.7,
"baseSeverity": "MEDIUM",
"attackVector": "LOCAL",
"attackComplexity": "HIGH",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"availabilityImpact": "HIGH"
},
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}
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},
"weaknesses": [
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"source": "[email protected]",
"type": "Primary",
"description": [
{
"lang": "en",
"value": "CWE-362"
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{
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