Vulnerability-Lookup

GHSA-4PQP-H39M-GCW4

Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 12:30

Details

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

usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers()

Previously fsg_num_buffers_validate() was removed as it was not necessary due to Kconfig setting the limits for n from 2 to 256 with default as 2. However, setting the page content in such a way that kstrtou8() reflects n value as either 0 or 1 bypasses these restrictions leading to a null pointer dereference if n is 0. Fix this by adding a check for n < 2 and returning -EINVAL if n is either 0 or 1 consistent with Kconfig logic.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-90023"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T11:17:15Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers()\n\nPreviously fsg_num_buffers_validate() was removed as it was not\nnecessary due to Kconfig setting the limits for n from 2 to 256 with\ndefault as 2. However, setting the page content in such a way that\nkstrtou8() reflects n value as either 0 or 1 bypasses these\nrestrictions leading to a null pointer dereference if n is 0. Fix\nthis by adding a check for n \u003c 2 and returning -EINVAL if n is\neither 0 or 1 consistent with Kconfig logic.",
  "id": "GHSA-4pqp-h39m-gcw4",
  "modified": "2026-09-16T12:30:45Z",
  "published": "2026-09-16T12:30:45Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90023"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2c0f5ca48674a5b5f9fa4a9c3325aa48053af0bc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9e8dd2a7a8ccbb756771ad985b0ad3387ed3c957"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b9b5b5df5b8dd3c1572ed267200276a44cc67d8e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-90023 (GCVE-0-2026-90023)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:33 – Updated: 2026-09-16 10:33

Title

usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers()

Summary

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers() Previously fsg_num_buffers_validate() was removed as it was not necessary due to Kconfig setting the limits for n from 2 to 256 with default as 2. However, setting the page content in such a way that kstrtou8() reflects n value as either 0 or 1 bypasses these restrictions leading to a null pointer dereference if n is 0. Fix this by adding a check for n < 2 and returning -EINVAL if n is either 0 or 1 consistent with Kconfig logic.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/9e8dd2a7a8ccbb756…
https://git.kernel.org/stable/c/b9b5b5df5b8dd3c15…
https://git.kernel.org/stable/c/2c0f5ca48674a5b5f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: fe5a6c48fd954489f51aab151d5dad9254c76419 , < 9e8dd2a7a8ccbb756771ad985b0ad3387ed3c957 (git) Affected: fe5a6c48fd954489f51aab151d5dad9254c76419 , < b9b5b5df5b8dd3c1572ed267200276a44cc67d8e (git) Affected: fe5a6c48fd954489f51aab151d5dad9254c76419 , < 2c0f5ca48674a5b5f9fa4a9c3325aa48053af0bc (git)
Linux	Linux	Affected: 4.8 Unaffected: 0 , < 4.8 (semver) Unaffected: 6.18.52 , ≤ 6.18.* (semver) Unaffected: 7.2.5 , ≤ 7.2.* (semver) Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_mass_storage.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9e8dd2a7a8ccbb756771ad985b0ad3387ed3c957",
              "status": "affected",
              "version": "fe5a6c48fd954489f51aab151d5dad9254c76419",
              "versionType": "git"
            },
            {
              "lessThan": "b9b5b5df5b8dd3c1572ed267200276a44cc67d8e",
              "status": "affected",
              "version": "fe5a6c48fd954489f51aab151d5dad9254c76419",
              "versionType": "git"
            },
            {
              "lessThan": "2c0f5ca48674a5b5f9fa4a9c3325aa48053af0bc",
              "status": "affected",
              "version": "fe5a6c48fd954489f51aab151d5dad9254c76419",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_mass_storage.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.8"
            },
            {
              "lessThan": "4.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc2",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers()\n\nPreviously fsg_num_buffers_validate() was removed as it was not\nnecessary due to Kconfig setting the limits for n from 2 to 256 with\ndefault as 2. However, setting the page content in such a way that\nkstrtou8() reflects n value as either 0 or 1 bypasses these\nrestrictions leading to a null pointer dereference if n is 0. Fix\nthis by adding a check for n \u003c 2 and returning -EINVAL if n is\neither 0 or 1 consistent with Kconfig logic."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T10:33:26.905Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9e8dd2a7a8ccbb756771ad985b0ad3387ed3c957"
        },
        {
          "url": "https://git.kernel.org/stable/c/b9b5b5df5b8dd3c1572ed267200276a44cc67d8e"
        },
        {
          "url": "https://git.kernel.org/stable/c/2c0f5ca48674a5b5f9fa4a9c3325aa48053af0bc"
        }
      ],
      "title": "usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90023",
    "datePublished": "2026-09-16T10:33:26.905Z",
    "dateReserved": "2026-09-11T19:38:34.782Z",
    "dateUpdated": "2026-09-16T10:33:26.905Z",
    "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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.