CVE-2026-63942

Estado: Pendiente de análisisAlta (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

parport: Fix race between port and client registration

The parport subsystem registers port devices before they are fully initialised, resulting in a race condition where client drivers such as lp can attach to ports that are not completely initialised or even being torn down.

When the port and client drivers are built as modules and loaded around the same time during boot, this occasionally results in a crash. I was able to make this happen reliably in a VM with a PC-style parallel port by patching parport_pc to fail probing:

> --- a/drivers/parport/parport_pc.c > +++ b/drivers/parport/parport_pc.c > @@ -2069,7 +2069,7 @@ static struct parport *__parport_pc_probe_port(unsigned long int base, > if (!p) > goto out3; > > - base_res = request_region(base, 3, p->name); > + base_res = NULL; > if (!base_res) > goto out4; >

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and then running:

for a few seconds.

In the long term I think port registration should be changed to put the call to device_add() inside parport_announce_port(), but since the latter currently cannot fail this will require changing all port drivers.

For now, add a flag to indicate whether a port has been "announced" and only try to attach client drivers to ports when the flag is set.

Detalles técnicos trazas, registros y código del informe original

    while true; do
        modprobe lp & modprobe parport_pc
	wait
	rmmod lp parport_pc
    done

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.18%
Percentil entre todas las CVEs puntuadas: 6
Fecha de la puntuación: 6/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation60 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence Program Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-63942",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
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  "published": "2026-07-19T16:17:12.747",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nparport: Fix race between port and client registration\n\nThe parport subsystem registers port devices before they are fully\ninitialised, resulting in a race condition where client drivers such\nas lp can attach to ports that are not completely initialised or even\nbeing torn down.\n\nWhen the port and client drivers are built as modules and loaded\naround the same time during boot, this occasionally results in a\ncrash.  I was able to make this happen reliably in a VM with a\nPC-style parallel port by patching parport_pc to fail probing:\n\n> --- a/drivers/parport/parport_pc.c\n> +++ b/drivers/parport/parport_pc.c\n> @@ -2069,7 +2069,7 @@ static struct parport *__parport_pc_probe_port(unsigned long int base,\n>  \tif (!p)\n>  \t\tgoto out3;\n>\n> -\tbase_res = request_region(base, 3, p->name);\n> +\tbase_res = NULL;\n>  \tif (!base_res)\n>  \t\tgoto out4;\n>\n\nand then running:\n\n    while true; do\n        modprobe lp & modprobe parport_pc\n\twait\n\trmmod lp parport_pc\n    done\n\nfor a few seconds.\n\nIn the long term I think port registration should be changed to put\nthe call to device_add() inside parport_announce_port(), but since the\nlatter currently cannot fail this will require changing all port\ndrivers.\n\nFor now, add a flag to indicate whether a port has been \"announced\"\nand only try to attach client drivers to ports when the flag is set."
    }
  ],
  "lastModified": "2026-07-27T17:44:23.777",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}