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CVE-2026-98764

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

Products / packages Linux

Published

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Severity and exploitation

Not in CISA KEVNo CVSS score

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 21:40:35 UTC

Severity

unknown

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Fix status not established

No structured fix or guidance is available here. Check the latest publisher advisory.

What this means

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

Source excerpt · Linux

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Linux · Linux

Linux

8 ranges
Linux version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

c559a353410939c0884e83bdb0e2420a986ac53b → before c5f452e057df6ef89300523d13ad6833bfd199cd

git versions

c559a353410939c0884e83bdb0e2420a986ac53b → before e5b9d6bb2a8906a1188c9a90cc8d102de3f07cad

git versions

c559a353410939c0884e83bdb0e2420a986ac53b → before 7ef0ad5f462fa95bc4c6647d097d7c0384245b9c

git versions

c559a353410939c0884e83bdb0e2420a986ac53b → before 06ac8609d6d185ac18c1d6a6a8a9b99e398bd124

git versions

c559a353410939c0884e83bdb0e2420a986ac53b → before 9d8761b3c133f6c6a6d3486839dac60e2cf4bfe3

git versions

c559a353410939c0884e83bdb0e2420a986ac53b → before 7811d8e26c77f8eea79e22d0d14c67ec0658b348

git versions

c559a353410939c0884e83bdb0e2420a986ac53b → before 35ab269602e1f7c4c0fe6ea3477264bea77eced3

git versions

c559a353410939c0884e83bdb0e2420a986ac53b → before 9cd072788c76595529eb38f42bf94d23852f8534

git versions

unaffected

unknown

Other versions: unaffected

Linux · Linux

Linux

10 ranges
Linux version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

3.18

unaffected

0 → before 3.18

semver versions

5.10.273 → through 5.10.*

semver versions

5.15.224 → through 5.15.*

semver versions

6.1.191 → through 6.1.*

semver versions

6.6.160 → through 6.6.*

semver versions

6.12.113 → through 6.12.*

semver versions

6.18.56 → through 6.18.*

semver versions

7.2.10 → through 7.2.*

semver versions

7.3 → through *

original_commit_for_fix versions

unknown

Other versions: affected

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

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 descriptor is found. In addition, mark desc as const to match struct usb_ep::desc and avoid discarding qualifiers.

References

8 sources
git.kernel.org/stable/c/c5f452e057df6ef89300523d13ad6833bfd199cd
Source referenceLinux
git.kernel.org/stable/c/e5b9d6bb2a8906a1188c9a90cc8d102de3f07cad
Source referenceLinux
git.kernel.org/stable/c/7ef0ad5f462fa95bc4c6647d097d7c0384245b9c
Source referenceLinux
git.kernel.org/stable/c/06ac8609d6d185ac18c1d6a6a8a9b99e398bd124
Source referenceLinux
git.kernel.org/stable/c/9d8761b3c133f6c6a6d3486839dac60e2cf4bfe3
Source referenceLinux
git.kernel.org/stable/c/7811d8e26c77f8eea79e22d0d14c67ec0658b348
Source referenceLinux
View 2 more references
git.kernel.org/stable/c/35ab269602e1f7c4c0fe6ea3477264bea77eced3
Source referenceLinux
git.kernel.org/stable/c/9cd072788c76595529eb38f42bf94d23852f8534
Source referenceLinux

Inside the record

Evidence available

Package identity · not supplied
Version evidence
Remediation guidance · not supplied
Weakness classification · not supplied
Additional publishers · not supplied

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-98764

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

Linux · platform conditions

Any condition may hold

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.18

Before: 5.10.273

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.18

Before: 5.15.224

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.18

Before: 6.1.191

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.18

Before: 6.6.160

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.18

Before: 6.12.113

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.18

Before: 6.18.56

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.18

Before: 7.2.10

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.18

Before: 7.3

Applicability preview
[
  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.18",
            "versionEndExcluding": "5.10.273"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.18",
            "versionEndExcluding": "5.15.224"
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          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.18",
            "versionEndExcluding": "6.1.191"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.18",
            "versionEndExcluding": "6.6.160"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.18",
            "versionEndExcluding": "6.12.113"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.18",
            "versionEndExcluding": "6.18.56"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.18",
            "versionEndExcluding": "7.2.10"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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            "versionEndExcluding": "7.3"
          }
        ]
      }
    ]
  }
]
Contributing organizations · 1
Linux

Assigning organization

2026-10-30

Timeline

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  1. Advisory published

    Publication date supplied by the source.

  2. Source updated

    Latest modification date supplied by the source.

  3. Last imported by cve.new

    Latest catalog import, not the date we first saw this advisory.

What changed

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