CVE-2026-90022 (GCVE-0-2026-90022)
Vulnerability from cvelistv5
Published
2026-09-16 10:33
Modified
2026-10-19 08:56
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: usb: gadget: f_midi2: fix use-after-free in string attribute show path f_midi2_opts_str_show() takes the string lock internally, but its callers dereference the opts->info.<field> pointer before calling it, outside the lock. This races with f_midi2_opts_str_store(), which frees the old string under opts->lock when the attribute is written concurrently, the show path can read a pointer that gets freed before the lock inside str_show() is even taken. Change f_midi2_opts_str_show() to take a pointer to the string field, matching the existing pattern in f_midi2_opts_str_store(), and dereference it only after the lock is held. Update all three callers (iface_name, block name, and the EP string option macro) accordingly.
References
Impacted products
Vendor Product Version
Linux Linux Version: 29ee7a4dddd5caa18d1cef000f20c6af43f762f1
Version: 29ee7a4dddd5caa18d1cef000f20c6af43f762f1
Version: 29ee7a4dddd5caa18d1cef000f20c6af43f762f1
Version: 29ee7a4dddd5caa18d1cef000f20c6af43f762f1
Version: 29ee7a4dddd5caa18d1cef000f20c6af43f762f1
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_midi2.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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            {
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              "versionType": "git"
            },
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              "status": "affected",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_midi2.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.6"
            },
            {
              "lessThan": "6.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_midi2: fix use-after-free in string attribute show path\n\nf_midi2_opts_str_show() takes the string lock internally, but its\ncallers dereference the opts-\u003einfo.\u003cfield\u003e pointer before calling it,\noutside the lock. This races with f_midi2_opts_str_store(), which\nfrees the old string under opts-\u003elock when the attribute is written\nconcurrently, the show path can read a pointer that gets freed\nbefore the lock inside str_show() is even taken.\n\nChange f_midi2_opts_str_show() to take a pointer to the string field,\nmatching the existing pattern in f_midi2_opts_str_store(), and\ndereference it only after the lock is held. Update all three callers\n(iface_name, block name, and the EP string option macro) accordingly."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached by concurrent local read/write of midi2 configfs string attributes (iface_name, ep_name, product_id, block name) under /sys/kernel/config/usb_gadget/\u003cg\u003e/functions/midi2.*; no USB host packets, cable, or UDC bind are required, matching other gadget configfs bugs scored Local rather than Physical.\nAC:L - The attacker controls both sides by opening the same attribute on two fds (configfs serializes only per-fd) and racing show against store; store kfree()s the prior kstrndup string under opts-\u003elock while show already holds the stale pointer, and the function need not be bound (store fails only if refcnt != 0).\nPR:L - gadgets_make(), function_make(), and the midi2 show/store handlers perform no capable() check; access is gated only by configfs DAC, and Android/embedded USB gadget HALs routinely chown /sys/kernel/config/usb_gadget to non-root system or daemon accounts.\nUI:N - The attacker creates the midi2 function instance and performs the concurrent attribute read/write themselves; configfs is typically already mounted at /sys/kernel/config, and no victim mount, cable plug, or other-user action is required.\nS:U - The use-after-free of the configfs kstrndup string corrupts kernel heap within the same host kernel security authority; this is not a VM escape, sandbox breakout, or IOMMU/DMA boundary bypass.\nC:H - Callers load opts-\u003einfo.\u003cfield\u003e outside the lock, then f_midi2_opts_str_show() scnprintfs that pointer after a concurrent store kfree()d it; reclaiming the kmalloc object lets the attacker control the bytes copied to userspace, a UAF disclosure primitive.\nI:H - The same UAF of the kstrndup string, with store spraying attacker-chosen size and content into the same slab, is a classic heap use-after-free that can be converted into overlapping objects, arbitrary write, and control-flow hijack.\nA:H - scnprintf() of the freed string after kfree() reliably produces a KASAN slab-use-after-free oops or kernel panic, which the attacker can retrigger with further concurrent show/store loops."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:56:35.790Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f9bdf4c4f6410a1dfafafa383a0e21069372657f"
        },
        {
          "url": "https://git.kernel.org/stable/c/d11f3300b39e2daad2f0d9d66ddcc39a156cb594"
        },
        {
          "url": "https://git.kernel.org/stable/c/e89e30f0b5d3004fe5955250bd8b04f3733e32ce"
        },
        {
          "url": "https://git.kernel.org/stable/c/49fab5e1bdb205c36c965d0e9677bc40d282d3a2"
        },
        {
          "url": "https://git.kernel.org/stable/c/fed0aa7c6eaedc6c0d4e362fc91724aa47be4a7b"
        }
      ],
      "title": "usb: gadget: f_midi2: fix use-after-free in string attribute show path",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90022",
    "datePublished": "2026-09-16T10:33:26.238Z",
    "dateReserved": "2026-09-11T19:38:34.781Z",
    "dateUpdated": "2026-10-19T08:56:35.790Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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