FKIE_CVE-2026-99227

Vulnerability from fkie_nvd - Published: 2026-11-02 16:17 - Updated: 2026-11-03 20:18
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/waitid: prevent cancel reference wrap io_waitid packs the cancellation state into bit 31 of ->refs and uses bits 30:0 as a 31-bit reference counter: #define IO_WAITID_CANCEL_FLAG BIT(31) #define IO_WAITID_REF_MASK GENMASK(30, 0) __io_waitid_cancel() marks a request canceled, then increments the low bits of ->refs to claim completion ownership. When another path owns the request, the increment remains even though cancellation returns false. The request remains discoverable by cancellation, so repeated failed attempts can wrap the 31-bit reference field to zero. A later cancellation can claim ownership and complete the request a second time. Use atomic_fetch_or() when setting the cancel flag and inspect the old flag value. The first cancel attempt continues to the existing ownership increment, preserving its wake and issuer handoff semantics. Later attempts see the cancel flag and return without incrementing the reference field. This makes repeated failed cancellation attempts idempotent while leaving the first-cancel state transitions unchanged.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/20b67288574c7c3df6b8ea7ed3b7af90a868006f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/22fb4a4518e305164c7f203608287564de292f34
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5bfeee1774791602a0d53eb717f00f172127a017
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/857aa2012b91cad6fdef54a4b6c632d9d0b6e64f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/98787d3fa4e99564d2b2bc21255b21f670c450d0
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "io_uring/waitid.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "20b67288574c7c3df6b8ea7ed3b7af90a868006f",
              "status": "affected",
              "version": "f31ecf671ddc498f20219453395794ff2383e06b",
              "versionType": "git"
            },
            {
              "lessThan": "5bfeee1774791602a0d53eb717f00f172127a017",
              "status": "affected",
              "version": "f31ecf671ddc498f20219453395794ff2383e06b",
              "versionType": "git"
            },
            {
              "lessThan": "857aa2012b91cad6fdef54a4b6c632d9d0b6e64f",
              "status": "affected",
              "version": "f31ecf671ddc498f20219453395794ff2383e06b",
              "versionType": "git"
            },
            {
              "lessThan": "22fb4a4518e305164c7f203608287564de292f34",
              "status": "affected",
              "version": "f31ecf671ddc498f20219453395794ff2383e06b",
              "versionType": "git"
            },
            {
              "lessThan": "98787d3fa4e99564d2b2bc21255b21f670c450d0",
              "status": "affected",
              "version": "f31ecf671ddc498f20219453395794ff2383e06b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "io_uring/waitid.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.7"
            },
            {
              "lessThan": "6.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.115",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.60",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.3.*",
              "status": "unaffected",
              "version": "7.3.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.4-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\nio_uring/waitid: prevent cancel reference wrap\n\nio_waitid packs the cancellation state into bit 31 of -\u003erefs and uses\nbits 30:0 as a 31-bit reference counter:\n\n  #define IO_WAITID_CANCEL_FLAG BIT(31)\n  #define IO_WAITID_REF_MASK    GENMASK(30, 0)\n\n__io_waitid_cancel() marks a request canceled, then increments the low\nbits of -\u003erefs to claim completion ownership. When another path owns the\nrequest, the increment remains even though cancellation returns false.\nThe request remains discoverable by cancellation, so repeated failed\nattempts can wrap the 31-bit reference field to zero. A later\ncancellation can claim ownership and complete the request a second time.\n\nUse atomic_fetch_or() when setting the cancel flag and inspect the old\nflag value. The first cancel attempt continues to the existing ownership\nincrement, preserving its wake and issuer handoff semantics. Later\nattempts see the cancel flag and return without incrementing the\nreference field.\n\nThis makes repeated failed cancellation attempts idempotent while\nleaving the first-cancel state transitions unchanged."
    }
  ],
  "id": "CVE-2026-99227",
  "lastModified": "2026-11-03T20:18:28.357",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-11-02T16:17:47.420",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/20b67288574c7c3df6b8ea7ed3b7af90a868006f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/22fb4a4518e305164c7f203608287564de292f34"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5bfeee1774791602a0d53eb717f00f172127a017"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/857aa2012b91cad6fdef54a4b6c632d9d0b6e64f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/98787d3fa4e99564d2b2bc21255b21f670c450d0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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