FKIE_CVE-2026-63942

Vulnerability from fkie_nvd - Published: 2026-07-19 16:17 - Updated: 2026-07-20 15:16
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
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; > and then running: while true; do modprobe lp & modprobe parport_pc wait rmmod lp parport_pc done 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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/15b1723c1472e802f9f7e69ae4e64f7dbf588848
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/290f515c5e3b3900bc2fe24f179999fd08d23bfa
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/51026cff1f4f3b762a0b5a07c727bd59cef45320
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/74d6aae1df45d3414178986be743f946988fddf6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a1e81b58da0179531bedf0b9f2811f5f992d5c4b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d16548be2ea5058227d79799e81dab61c9bca8ec
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ef15ccbb3e8640a723c42ad90eaf81d66ae02017
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f3378b0d7bd4605de89b083b2900788157a181cc
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/parport/share.c",
            "include/linux/parport.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f3378b0d7bd4605de89b083b2900788157a181cc",
              "status": "affected",
              "version": "6fa45a22689722dac9f0e90c0931d4b34b334ede",
              "versionType": "git"
            },
            {
              "lessThan": "290f515c5e3b3900bc2fe24f179999fd08d23bfa",
              "status": "affected",
              "version": "6fa45a22689722dac9f0e90c0931d4b34b334ede",
              "versionType": "git"
            },
            {
              "lessThan": "d16548be2ea5058227d79799e81dab61c9bca8ec",
              "status": "affected",
              "version": "6fa45a22689722dac9f0e90c0931d4b34b334ede",
              "versionType": "git"
            },
            {
              "lessThan": "15b1723c1472e802f9f7e69ae4e64f7dbf588848",
              "status": "affected",
              "version": "6fa45a22689722dac9f0e90c0931d4b34b334ede",
              "versionType": "git"
            },
            {
              "lessThan": "51026cff1f4f3b762a0b5a07c727bd59cef45320",
              "status": "affected",
              "version": "6fa45a22689722dac9f0e90c0931d4b34b334ede",
              "versionType": "git"
            },
            {
              "lessThan": "74d6aae1df45d3414178986be743f946988fddf6",
              "status": "affected",
              "version": "6fa45a22689722dac9f0e90c0931d4b34b334ede",
              "versionType": "git"
            },
            {
              "lessThan": "a1e81b58da0179531bedf0b9f2811f5f992d5c4b",
              "status": "affected",
              "version": "6fa45a22689722dac9f0e90c0931d4b34b334ede",
              "versionType": "git"
            },
            {
              "lessThan": "ef15ccbb3e8640a723c42ad90eaf81d66ae02017",
              "status": "affected",
              "version": "6fa45a22689722dac9f0e90c0931d4b34b334ede",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/parport/share.c",
            "include/linux/parport.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.2"
            },
            {
              "lessThan": "4.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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\u003e --- a/drivers/parport/parport_pc.c\n\u003e +++ b/drivers/parport/parport_pc.c\n\u003e @@ -2069,7 +2069,7 @@ static struct parport *__parport_pc_probe_port(unsigned long int base,\n\u003e  \tif (!p)\n\u003e  \t\tgoto out3;\n\u003e\n\u003e -\tbase_res = request_region(base, 3, p-\u003ename);\n\u003e +\tbase_res = NULL;\n\u003e  \tif (!base_res)\n\u003e  \t\tgoto out4;\n\u003e\n\nand then running:\n\n    while true; do\n        modprobe lp \u0026 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."
    }
  ],
  "id": "CVE-2026-63942",
  "lastModified": "2026-07-20T15:16:57.970",
  "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": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-19T16:17:12.747",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/15b1723c1472e802f9f7e69ae4e64f7dbf588848"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/290f515c5e3b3900bc2fe24f179999fd08d23bfa"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/51026cff1f4f3b762a0b5a07c727bd59cef45320"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/74d6aae1df45d3414178986be743f946988fddf6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a1e81b58da0179531bedf0b9f2811f5f992d5c4b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d16548be2ea5058227d79799e81dab61c9bca8ec"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ef15ccbb3e8640a723c42ad90eaf81d66ae02017"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f3378b0d7bd4605de89b083b2900788157a181cc"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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