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GHSA-G7V6-7VR9-25JQ

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33

Details

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

gpib: fix double decrement of descriptor_busy in command_ioctl()

commit d1857f8296dc ("gpib: fix use-after-free in IO ioctl handlers") introduced a descriptor_busy reference counter to pin struct gpib_descriptor across IO ioctl operations. In command_ioctl(), the error path inside the loop decrements descriptor_busy and breaks, but execution then falls through to the unconditional decrement after the loop, underflowing the counter to -1.

This re-enables the use-after-free that the original fix was meant to prevent: a concurrent close_dev_ioctl() sees descriptor_busy == 0 on an actively-used descriptor and frees it.

Remove the early decrement from the error path. The post-loop decrement already handles all exit paths, matching the correct pattern used in read_ioctl() and write_ioctl().

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72482"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:22:22Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ngpib: fix double decrement of descriptor_busy in command_ioctl()\n\ncommit d1857f8296dc (\"gpib: fix use-after-free in IO ioctl handlers\")\nintroduced a descriptor_busy reference counter to pin struct\ngpib_descriptor across IO ioctl operations.  In command_ioctl(), the\nerror path inside the loop decrements descriptor_busy and breaks, but\nexecution then falls through to the unconditional decrement after the\nloop, underflowing the counter to -1.\n\nThis re-enables the use-after-free that the original fix was meant to\nprevent: a concurrent close_dev_ioctl() sees descriptor_busy == 0 on\nan actively-used descriptor and frees it.\n\nRemove the early decrement from the error path.  The post-loop\ndecrement already handles all exit paths, matching the correct pattern\nused in read_ioctl() and write_ioctl().",
  "id": "GHSA-g7v6-7vr9-25jq",
  "modified": "2026-08-17T06:33:32Z",
  "published": "2026-08-15T06:32:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72482"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8b5f1d295dda8677e4545ce340053fcfa8b634c7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c4faab452b3c1ada003d49c477609dd80523b9bf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fdee9f207a48ce204ec6cfceaa1459d2473600a5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-72482 (GCVE-0-2026-72482)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:57 – Updated: 2026-08-17 05:44

Title

gpib: fix double decrement of descriptor_busy in command_ioctl()

Summary

In the Linux kernel, the following vulnerability has been resolved: gpib: fix double decrement of descriptor_busy in command_ioctl() commit d1857f8296dc ("gpib: fix use-after-free in IO ioctl handlers") introduced a descriptor_busy reference counter to pin struct gpib_descriptor across IO ioctl operations. In command_ioctl(), the error path inside the loop decrements descriptor_busy and breaks, but execution then falls through to the unconditional decrement after the loop, underflowing the counter to -1. This re-enables the use-after-free that the original fix was meant to prevent: a concurrent close_dev_ioctl() sees descriptor_busy == 0 on an actively-used descriptor and frees it. Remove the early decrement from the error path. The post-loop decrement already handles all exit paths, matching the correct pattern used in read_ioctl() and write_ioctl().

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/fdee9f207a48ce204…
https://git.kernel.org/stable/c/8b5f1d295dda8677e…
https://git.kernel.org/stable/c/c4faab452b3c1ada0…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: cae26eff1b56d78bed7873cf3e60a2b1bdd4da6c , < fdee9f207a48ce204ec6cfceaa1459d2473600a5 (git) Affected: d1857f8296dceb75d00ab857fc3c61bc00c7f5c6 , < 8b5f1d295dda8677e4545ce340053fcfa8b634c7 (git) Affected: d1857f8296dceb75d00ab857fc3c61bc00c7f5c6 , < c4faab452b3c1ada003d49c477609dd80523b9bf (git) Affected: 28c75dd143ead62e0dfac564c79d251e21d5d74b (git) Affected: 6.18.22 , < 6.18.40 (semver) Affected: 6.19.12 , < 6.20 (semver)
Linux	Linux	Affected: 7.0 Unaffected: 0 , < 7.0 (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpib/common/gpib_os.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fdee9f207a48ce204ec6cfceaa1459d2473600a5",
              "status": "affected",
              "version": "cae26eff1b56d78bed7873cf3e60a2b1bdd4da6c",
              "versionType": "git"
            },
            {
              "lessThan": "8b5f1d295dda8677e4545ce340053fcfa8b634c7",
              "status": "affected",
              "version": "d1857f8296dceb75d00ab857fc3c61bc00c7f5c6",
              "versionType": "git"
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              "versionType": "git"
            },
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              "versionType": "git"
            },
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              "lessThan": "6.18.40",
              "status": "affected",
              "version": "6.18.22",
              "versionType": "semver"
            },
            {
              "lessThan": "6.20",
              "status": "affected",
              "version": "6.19.12",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpib/common/gpib_os.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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            {
              "lessThanOrEqual": "6.18.*",
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              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
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        }
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          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "6.18.22",
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                },
                {
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                }
              ],
              "negate": false,
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngpib: fix double decrement of descriptor_busy in command_ioctl()\n\ncommit d1857f8296dc (\"gpib: fix use-after-free in IO ioctl handlers\")\nintroduced a descriptor_busy reference counter to pin struct\ngpib_descriptor across IO ioctl operations.  In command_ioctl(), the\nerror path inside the loop decrements descriptor_busy and breaks, but\nexecution then falls through to the unconditional decrement after the\nloop, underflowing the counter to -1.\n\nThis re-enables the use-after-free that the original fix was meant to\nprevent: a concurrent close_dev_ioctl() sees descriptor_busy == 0 on\nan actively-used descriptor and frees it.\n\nRemove the early decrement from the error path.  The post-loop\ndecrement already handles all exit paths, matching the correct pattern\nused in read_ioctl() and write_ioctl()."
        }
      ],
      "metrics": [
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            "baseSeverity": "HIGH",
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            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached only through local ioctl on /dev/gpibN character devices; exploitation requires concurrent IBCMD (command_ioctl) and IBCLOSEDEV calls, not remote network traffic or physical GPIB bus manipulation.\nAC:L - Once a GPIB board is online and accessible, an attacker controls both race participants by running a failing IBCMD ioctl in one thread and IBCLOSEDEV on the same handle in another; ibcmd errors (e.g., timeout or missing CIC) are reliably triggerable.\nPR:L - The vulnerable IBCMD and IBCLOSEDEV ioctls perform no capability checks; any local user with access to an already-configured, online GPIB device node can open handles and race command/close operations typical of lab and factory test automation accounts.\nUI:N - No victim interaction is required beyond the attacker already having local access to the GPIB device; exploitation is performed entirely through attacker-controlled ioctl sequences without needing another user to mount, open, or approve actions.\nS:U - This is a kernel heap use-after-free within the GPIB driver reachable from local process ioctls and affects the same kernel security authority; it does not cross virtualization, IOMMU, or separate security-scope boundaries.\nC:H - The erroneous early descriptor_busy decrement lets close_dev_ioctl kfree() the struct while command_ioctl still holds and dereferences it; freed kmalloc slab reuse can expose or help derive kernel memory contents per UAF scoring guidance.\nI:H - Post-free atomic writes to io_in_progress and descriptor_busy on the stale pointer can corrupt attacker-influenced reused heap objects, providing a plausible path to kernel data corruption, write primitives, or privilege escalation.\nA:H - Dereferencing the freed gpib_descriptor during IBCMD completion (atomic_set, atomic_dec, wake_up) can cause kernel oops, BUG, or panic; use-after-free bugs are scored as high availability impact even before full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:44:45.643Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/fdee9f207a48ce204ec6cfceaa1459d2473600a5"
        },
        {
          "url": "https://git.kernel.org/stable/c/8b5f1d295dda8677e4545ce340053fcfa8b634c7"
        },
        {
          "url": "https://git.kernel.org/stable/c/c4faab452b3c1ada003d49c477609dd80523b9bf"
        }
      ],
      "title": "gpib: fix double decrement of descriptor_busy in command_ioctl()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72482",
    "datePublished": "2026-08-15T05:57:20.247Z",
    "dateReserved": "2026-08-09T03:40:39.935Z",
    "dateUpdated": "2026-08-17T05:44:45.643Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

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.

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GHSA-G7V6-7VR9-25JQ

CVE-2026-72482 (GCVE-0-2026-72482)

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Sightings

Nomenclature