FKIE_CVE-2026-64289

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: iommufd: Set upper bounds on cache invalidation entry_num and entry_len iommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len, each bounded only by U32_MAX. An entry_len beyond the kernel's struct size makes the copy helper verify the extra bytes are zero, scanning that excess in one uninterruptible pass; a multi-gigabyte value over zeroed user memory trips the soft-lockup watchdog. A large entry_num is the other half, driving the backend invalidation loop with no reschedule. The VT-d nested handler, for one, copies each entry and flushes caches per iteration, pinning the CPU on a non-preemptible kernel. Cap both in the ioctl. entry_len is held under PAGE_SIZE, above any request struct, and entry_num under 1 << 19, the order of a hardware invalidation queue and well beyond any real batch, bounding the per-call loop length.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2c6381d90898089287e0a358f06f89f6b4b389f2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/32ca4aed2a66205b072fcfecabe220289a8149ff
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4d70986002f2f3eaaed89124fb2522bded38b016
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d2bd041e0efaf7d81789779b135279d18b33d6d5
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/iommufd/hw_pagetable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d2bd041e0efaf7d81789779b135279d18b33d6d5",
              "status": "affected",
              "version": "8c6eabae3807e048b9f17733af5e20500fbf858c",
              "versionType": "git"
            },
            {
              "lessThan": "32ca4aed2a66205b072fcfecabe220289a8149ff",
              "status": "affected",
              "version": "8c6eabae3807e048b9f17733af5e20500fbf858c",
              "versionType": "git"
            },
            {
              "lessThan": "2c6381d90898089287e0a358f06f89f6b4b389f2",
              "status": "affected",
              "version": "8c6eabae3807e048b9f17733af5e20500fbf858c",
              "versionType": "git"
            },
            {
              "lessThan": "4d70986002f2f3eaaed89124fb2522bded38b016",
              "status": "affected",
              "version": "8c6eabae3807e048b9f17733af5e20500fbf858c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/iommufd/hw_pagetable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.8"
            },
            {
              "lessThan": "6.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "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\niommufd: Set upper bounds on cache invalidation entry_num and entry_len\n\niommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len,\neach bounded only by U32_MAX. An entry_len beyond the kernel\u0027s struct size\nmakes the copy helper verify the extra bytes are zero, scanning that excess\nin one uninterruptible pass; a multi-gigabyte value over zeroed user memory\ntrips the soft-lockup watchdog.\n\nA large entry_num is the other half, driving the backend invalidation loop\nwith no reschedule. The VT-d nested handler, for one, copies each entry and\nflushes caches per iteration, pinning the CPU on a non-preemptible kernel.\n\nCap both in the ioctl. entry_len is held under PAGE_SIZE, above any request\nstruct, and entry_num under 1 \u003c\u003c 19, the order of a hardware invalidation\nqueue and well beyond any real batch, bounding the per-call loop length."
    }
  ],
  "id": "CVE-2026-64289",
  "lastModified": "2026-07-30T15:00:27.343",
  "metrics": {},
  "published": "2026-07-25T10:17:09.603",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2c6381d90898089287e0a358f06f89f6b4b389f2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/32ca4aed2a66205b072fcfecabe220289a8149ff"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4d70986002f2f3eaaed89124fb2522bded38b016"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d2bd041e0efaf7d81789779b135279d18b33d6d5"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}



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