CVE-2026-64217 (GCVE-0-2026-64217)

Vulnerability from cvelistv5 – Published: 2026-07-24 15:23 – Updated: 2026-08-05 12:40
VLAI
Title
netfs: Fix overrun check in netfs_extract_user_iter()
Summary
In the Linux kernel, the following vulnerability has been resolved: netfs: Fix overrun check in netfs_extract_user_iter() Fix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills pages[], then those pages don't get included in the iterator constructed at the end of the function. If there was an overfill, memory corruption has already happened.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 85dd2c8ff368b1446be9febde84afe1d7aec4261 , < 00efe58bbdcc93272d579ca24bfc912563f4a204 (git)
Affected: 85dd2c8ff368b1446be9febde84afe1d7aec4261 , < 96cc3beb2390ba9f9c128c5733c0ccfe450dd4f9 (git)
Affected: 85dd2c8ff368b1446be9febde84afe1d7aec4261 , < afeb32d9bf9aaeea51d0f723a19f14afb73bd94d (git)
Affected: 85dd2c8ff368b1446be9febde84afe1d7aec4261 , < f48b9157f0f611fa436c360648603d5ded719b12 (git)
Affected: 85dd2c8ff368b1446be9febde84afe1d7aec4261 , < 0ef37eef83fad3542ee06db2940433ae1a92b39d (git)
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Linux Linux Affected: 6.3
Unaffected: 0 , < 6.3 (semver)
Unaffected: 6.6.142 , ≤ 6.6.* (semver)
Unaffected: 6.12.92 , ≤ 6.12.* (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/netfs/iterator.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix overrun check in netfs_extract_user_iter()\n\nFix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills\npages[], then those pages don\u0027t get included in the iterator constructed at\nthe end of the function.  If there was an overfill, memory corruption has\nalready happened."
        }
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            "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": [
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              "lang": "en",
              "value": "AV:L - The vulnerable helper is reached through local direct or unbuffered I/O against CIFS/SMB3, AFS, or 9P files. Remote peers cannot directly control the local user iterator that triggers extraction.\nAC:L - The attacker controls and can repeatedly submit the UBUF or IOVEC layout, and corruption occurs synchronously once the overfill condition is reached. No race, timing window, or victim-controlled state is required.\nPR:L - An ordinary unprivileged process with permission to access a file on an existing affected mount can reach the helper. No capability or administrative privilege is checked on the I/O path.\nUI:N - The attacker directly opens and performs I/O on the accessible file without requiring another user to act. An existing affected mount is a deployment prerequisite, not per-attack victim interaction.\nS:U - The corruption compromises the same host kernel that processes the local I/O. It does not inherently cross a VM, IOMMU, or other distinct security authority.\nC:H - The overfill writes page pointers beyond the allocated kernel buffer and the malformed bvec can subsequently access unpopulated descriptors. Exploitation of this kernel heap corruption can expose arbitrary kernel memory.\nI:H - The bug produces an out-of-bounds kernel heap write and can cause adjacent memory to be interpreted as bvec descriptors. Heap grooming could turn this into arbitrary memory modification or control-flow hijacking.\nA:H - The corruption can cause a kernel oops, panic, or hang, while aborted extraction can also leak pinned pages. An attacker can repeat the triggering I/O to sustain denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:40:05.203Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/00efe58bbdcc93272d579ca24bfc912563f4a204"
        },
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          "url": "https://git.kernel.org/stable/c/96cc3beb2390ba9f9c128c5733c0ccfe450dd4f9"
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        {
          "url": "https://git.kernel.org/stable/c/0ef37eef83fad3542ee06db2940433ae1a92b39d"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64217",
    "datePublished": "2026-07-24T15:23:05.261Z",
    "dateReserved": "2026-07-19T15:36:31.770Z",
    "dateUpdated": "2026-08-05T12:40:05.203Z",
    "state": "PUBLISHED"
  },
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    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-05T12:04:37+00:00",
      "cve": "CVE-2026-64217",
      "id": "CVE-2026-64217",
      "initial_release_date": "2026-07-24T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "199",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: netfs: Fix overrun check in netfs_extract_user_iter()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64217.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-07-30T16:32:48Z",
      "cve": "CVE-2026-64217",
      "id": "CVE-2026-64217",
      "initial_release_date": "2026-07-25T00:14:21Z",
      "product_status:known_affected": "131",
      "product_status:known_not_affected": "167",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64217",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64217.json",
      "version": "5"
    }
  }
}



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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

Author Source Type Date Other

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.