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CVE-2026-64264 (GCVE-0-2026-64264)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:49 – Updated: 2026-08-17 04:52
VLAI
Title
fuse-uring: fix EFAULT clobber in fuse_uring_commit
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.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c090c8abae4b6b77a1bee116aa6c385456ebef96 , < 0483fffdeeb363f320e6bf5fc0f0306007507306 (git)
Affected: c090c8abae4b6b77a1bee116aa6c385456ebef96 , < fe604c08d874648a69187f6380e5c7858627dc04 (git)
Affected: c090c8abae4b6b77a1bee116aa6c385456ebef96 , < 3a0a8bc51a13951c5141262bf770eeea3e0b6228 (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.39 , ≤ 6.18.* (semver)
Unaffected: 7.1.4 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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      "affected": [
        {
          "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": [
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              "status": "affected",
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              "versionType": "git"
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          "versions": [
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          "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."
        }
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          "url": "https://git.kernel.org/stable/c/0483fffdeeb363f320e6bf5fc0f0306007507306"
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          "url": "https://git.kernel.org/stable/c/3a0a8bc51a13951c5141262bf770eeea3e0b6228"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64264",
    "datePublished": "2026-07-25T08:49:13.891Z",
    "dateReserved": "2026-07-19T15:36:31.774Z",
    "dateUpdated": "2026-08-17T04:52:17.918Z",
    "state": "PUBLISHED"
  },
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    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-07-29T15:43:37+00:00",
      "cve": "CVE-2026-64264",
      "id": "CVE-2026-64264",
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      "cve": "CVE-2026-64264",
      "id": "CVE-2026-64264",
      "initial_release_date": "2026-07-25T16:47:02Z",
      "product_status:known_not_affected": "298",
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      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64264",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64264.json",
      "version": "4"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.


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.