Skip to content
Heist/ feed
Unrated

usb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC When user space sets up FunctionFS with only full-speed descriptors (e.g., flags = FUNCTIONFS_HAS_FS_DESC) and the gadget operates at a higher speed (such as USB_SPEED_HIGH or USB_SPEED_SUPER), config_ep_by_speed() detects that the function lacks descriptors for the current speed, logs a warning, and falls back to full-speed descriptors. The endpoint is then successfully enabled via usb_ep_enable(), and epfile->ep becomes valid. However, when user space subsequently issues the FUNCTIONFS_ENDPOINT_DESC ioctl to query the endpoint descriptor, ffs_epfile_ioctl() selects the descriptor index solely based on gadget->speed: switch (epfile->ffs->gadget->speed) { case USB_SPEED_SUPER: case USB_SPEED_SUPER_PLUS: desc_idx = 2; break; case USB_SPEED_HIGH: desc_idx = 1; break; default: desc_idx = 0; } desc = epfile->ep->descs[desc_idx]; memcpy(&desc1, desc, desc->bLength); Because user space only supplied full-speed descriptors, epfile->ep->descs[1] is NULL. Dereferencing desc->bLength triggers an immediate kernel NULL pointer dereference panic. Fix this by falling back through lower speed descriptors if the current speed descriptor was not supplied, matching the fallback logic in config_ep_by_speed() and historical f_fs behavior. If still missing, fall back to epfile->ep->ep->desc (the active descriptor), and return -EINVAL safely if no valid de

Announced Source revision 1
Original source ↗

CVE-2026-98764

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98764

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "c559a353410939c0884e83bdb0e2420a986ac53b",
        "lessThan": "06ac8609d6d185ac18c1d6a6a8a9b99e398bd124",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c559a353410939c0884e83bdb0e2420a986ac53b",
        "lessThan": "9d8761b3c133f6c6a6d3486839dac60e2cf4bfe3",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c559a353410939c0884e83bdb0e2420a986ac53b",
        "lessThan": "7811d8e26c77f8eea79e22d0d14c67ec0658b348",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c559a353410939c0884e83bdb0e2420a986ac53b",
        "lessThan": "35ab269602e1f7c4c0fe6ea3477264bea77eced3",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c559a353410939c0884e83bdb0e2420a986ac53b",
        "lessThan": "9cd072788c76595529eb38f42bf94d23852f8534",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/usb/gadget/function/f_fs.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "3.18"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "3.18",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.113",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.56",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.10",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/usb/gadget/function/f_fs.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98764

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#48959 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement