CVE-2026-31554 (GCVE-0-2026-31554)
Vulnerability from cvelistv5
Published
2026-04-24 14:35
Modified
2026-08-05 12:23
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: futex: Require sys_futex_requeue() to have identical flags Nicholas reported that his LLM found it was possible to create a UaF when sys_futex_requeue() is used with different flags. The initial motivation for allowing different flags was the variable sized futex, but since that hasn't been merged (yet), simply mandate the flags are identical, as is the case for the old style sys_futex() requeue operations.
References
Impacted products
Vendor Product Version
Linux Linux Version: 0f4b5f972216782a4acb1ae00dcb55173847c2ff
Version: 0f4b5f972216782a4acb1ae00dcb55173847c2ff
Version: 0f4b5f972216782a4acb1ae00dcb55173847c2ff
Version: 0f4b5f972216782a4acb1ae00dcb55173847c2ff
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/futex/syscalls.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "027145ace09fad4c7cbcd6c61fe9b429c63eb0e5",
              "status": "affected",
              "version": "0f4b5f972216782a4acb1ae00dcb55173847c2ff",
              "versionType": "git"
            },
            {
              "lessThan": "18b7d09c2b794c71d4252f3ea2cf84ad12b73d6a",
              "status": "affected",
              "version": "0f4b5f972216782a4acb1ae00dcb55173847c2ff",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "0f4b5f972216782a4acb1ae00dcb55173847c2ff",
              "versionType": "git"
            },
            {
              "lessThan": "19f94b39058681dec64a10ebeb6f23fe7fc3f77a",
              "status": "affected",
              "version": "0f4b5f972216782a4acb1ae00dcb55173847c2ff",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/futex/syscalls.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": "6.12.80",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.21",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.80",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.21",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.11",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Require sys_futex_requeue() to have identical flags\n\nNicholas reported that his LLM found it was possible to create a UaF\nwhen sys_futex_requeue() is used with different flags. The initial\nmotivation for allowing different flags was the variable sized futex,\nbut since that hasn\u0027t been merged (yet), simply mandate the flags are\nidentical, as is the case for the old style sys_futex() requeue\noperations."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "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": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable code is reached through the local futex_requeue syscall path, not through network, adjacent, or physical input.\nAC:L - An unprivileged attacker can create the needed futex waiters, choose mismatched source and destination flags, and control the requeue/lifetime sequence; any race or timing is attacker-controlled.\nPR:L - The syscall has no capability or namespace gate, but the attacker needs basic local code execution to invoke futex syscalls and arrange the participating tasks.\nUI:N - No victim action is required; the attacker can trigger the vulnerable futex operations from their own processes/threads.\nS:U - The impact is within the kernel/local system security authority and is a standard local kernel memory corruption or privilege escalation scenario.\nC:H - The bug is a kernel use-after-free caused by requeueing waiters across incompatible private/shared futex hash lifetimes, which can plausibly be shaped into kernel memory disclosure.\nI:H - The use-after-free involves kernel heap/list/lock state reachable from attacker-controlled futex operations, making arbitrary kernel memory corruption or control-flow impact defensible.\nA:H - Even without full exploitation, dereferencing and manipulating freed futex hash bucket state can crash or hang the kernel."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:23:28.646Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/027145ace09fad4c7cbcd6c61fe9b429c63eb0e5"
        },
        {
          "url": "https://git.kernel.org/stable/c/18b7d09c2b794c71d4252f3ea2cf84ad12b73d6a"
        },
        {
          "url": "https://git.kernel.org/stable/c/e2f78c7ec1655fedd945366151ba54fcb9580508"
        },
        {
          "url": "https://git.kernel.org/stable/c/19f94b39058681dec64a10ebeb6f23fe7fc3f77a"
        }
      ],
      "title": "futex: Require sys_futex_requeue() to have identical flags",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31554",
    "datePublished": "2026-04-24T14:35:38.527Z",
    "dateReserved": "2026-03-09T15:48:24.115Z",
    "dateUpdated": "2026-08-05T12:23:28.646Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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