FKIE_CVE-2026-64264

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-07-30 15:00
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: fuse-uring: fix EFAULT clobber in fuse_uring_commit copy_from_user() returns the number of bytes not copied as an unsigned residual on failure (1..sizeof(struct fuse_out_header)). fuse_uring_commit stores that residual in ssize_t err, sets req->out.h.error to -EFAULT, then jumps to out: with err still holding the positive residual. err = copy_from_user(&req->out.h, &ent->headers->in_out, sizeof(req->out.h)); if (err) { req->out.h.error = -EFAULT; goto out; /* err is the positive residual */ } ... out: fuse_uring_req_end(ent, req, err); fuse_uring_req_end() then runs if (error) req->out.h.error = error; which overwrites the just-assigned -EFAULT with the positive residual. FUSE callers such as fuse_simple_request() test err < 0 to detect failure, so the positive value is interpreted as success and the caller proceeds with an uninitialised or partial req->out.args. Fix by assigning err = -EFAULT in the failure branch before jumping to out, so fuse_uring_req_end() receives a negative errno and sets req->out.h.error to -EFAULT.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0483fffdeeb363f320e6bf5fc0f0306007507306
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3a0a8bc51a13951c5141262bf770eeea3e0b6228
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fe604c08d874648a69187f6380e5c7858627dc04
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/fuse/dev_uring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0483fffdeeb363f320e6bf5fc0f0306007507306",
              "status": "affected",
              "version": "c090c8abae4b6b77a1bee116aa6c385456ebef96",
              "versionType": "git"
            },
            {
              "lessThan": "fe604c08d874648a69187f6380e5c7858627dc04",
              "status": "affected",
              "version": "c090c8abae4b6b77a1bee116aa6c385456ebef96",
              "versionType": "git"
            },
            {
              "lessThan": "3a0a8bc51a13951c5141262bf770eeea3e0b6228",
              "status": "affected",
              "version": "c090c8abae4b6b77a1bee116aa6c385456ebef96",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/fuse/dev_uring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfuse-uring: fix EFAULT clobber in fuse_uring_commit\n\ncopy_from_user() returns the number of bytes not copied as an unsigned\nresidual on failure (1..sizeof(struct fuse_out_header)). fuse_uring_commit\nstores that residual in ssize_t err, sets req-\u003eout.h.error to -EFAULT,\nthen jumps to out: with err still holding the positive residual.\n\n    err = copy_from_user(\u0026req-\u003eout.h, \u0026ent-\u003eheaders-\u003ein_out,\n                         sizeof(req-\u003eout.h));\n    if (err) {\n        req-\u003eout.h.error = -EFAULT;\n        goto out;          /* err is the positive residual */\n    }\n    ...\n    out:\n        fuse_uring_req_end(ent, req, err);\n\nfuse_uring_req_end() then runs\n\n    if (error)\n        req-\u003eout.h.error = error;\n\nwhich overwrites the just-assigned -EFAULT with the positive residual.\nFUSE callers such as fuse_simple_request() test err \u003c 0 to detect\nfailure, so the positive value is interpreted as success and the\ncaller proceeds with an uninitialised or partial req-\u003eout.args.\n\nFix by assigning err = -EFAULT in the failure branch before jumping\nto out, so fuse_uring_req_end() receives a negative errno and sets\nreq-\u003eout.h.error to -EFAULT."
    }
  ],
  "id": "CVE-2026-64264",
  "lastModified": "2026-07-30T15:00:27.343",
  "metrics": {},
  "published": "2026-07-25T10:17:06.563",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0483fffdeeb363f320e6bf5fc0f0306007507306"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3a0a8bc51a13951c5141262bf770eeea3e0b6228"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fe604c08d874648a69187f6380e5c7858627dc04"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}



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