{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 8.8,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "CHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2025-39698",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-09-26T03:55:13.138774Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-672",
                "description": "CWE-672 Operation on a Resource after Expiration or Release",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-02-26T17:49:11.880Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "io_uring/futex.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d9f93172820a53ab42c4b0e5e65291f4f9d00ad2",
              "status": "affected",
              "version": "194bb58c6090e39bd7d9b9c888a079213628e1f6",
              "versionType": "git"
            },
            {
              "lessThan": "d34c04152df517c59979b4bf2a47f491e06d3256",
              "status": "affected",
              "version": "194bb58c6090e39bd7d9b9c888a079213628e1f6",
              "versionType": "git"
            },
            {
              "lessThan": "508c1314b342b78591f51c4b5dadee31a88335df",
              "status": "affected",
              "version": "194bb58c6090e39bd7d9b9c888a079213628e1f6",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "io_uring/futex.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": "6.12.44",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.44",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16.4",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/futex: ensure io_futex_wait() cleans up properly on failure\n\nThe io_futex_data is allocated upfront and assigned to the io_kiocb\nasync_data field, but the request isn\u0027t marked with REQ_F_ASYNC_DATA\nat that point. Those two should always go together, as the flag tells\nio_uring whether the field is valid or not.\n\nAdditionally, on failure cleanup, the futex handler frees the data but\ndoes not clear -\u003easync_data. Clear the data and the flag in the error\npath as well.\n\nThanks to Trend Micro Zero Day Initiative and particularly ReDress for\nreporting this."
        }
      ],
      "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 vulnerability is reached purely through the io_uring interface \u2014 `io_uring_setup(2)` plus an SQE with `IORING_OP_FUTEX_WAIT` \u2014 which requires local code execution on the system. There is no remote or adjacent-network path into `io_futex_wait()`.\nAC:L - The failure path is hit deterministically by submitting a FUTEX_WAIT SQE whose `futex_val` does not match `*uaddr` (returns -EWOULDBLOCK) or with an unmapped `uaddr` (-EFAULT); no race or timing window is involved. The attacker also fully controls request recycling and heap grooming, since the freed `io_futex_data` lands in a general-purpose kmalloc cache and the sequence can be repeated arbitrarily.\nPR:L - `sysctl_io_uring_disabled` defaults to 0, so any unprivileged user can create a ring, and `IORING_OP_FUTEX_WAIT` requires no file, no capability, and no privileged setup (`io_futex_prep` only validates futex2 flags). No root or namespace trickery is needed.\nUI:N - The attacker submits all SQEs from their own process and drives the entire sequence \u2014 failing futex wait, request recycling, then POLL_ADD \u2014 with no action by any other user. No victim process or administrator involvement is required.\nS:U - The use-after-free occurs in kernel heap memory managed by the same kernel security authority as the attacking process. Exploitation yields kernel privilege escalation rather than crossing a VM, IOMMU, or other separate security boundary.\nC:H - The stale `req-\u003easync_data` is dereferenced as a `struct io_poll *` in `__io_queue_proc()` (`(*poll_ptr)-\u003ehead`), reading freed slab memory that the attacker can reclaim and shape, giving a controllable kernel-memory read/type-confusion primitive. Consistent with the guidance, a use-after-free of an attacker-reclaimable heap object is scored as High confidentiality impact.\nI:H - The dangling pointer is stored in a recycled `io_kiocb` and later treated as a live `struct io_poll`, so poll teardown (`io_poll_remove_entry()`\u0027s `list_del_init(\u0026poll-\u003ewait.entry)` / `poll-\u003ehead = NULL`) and `__io_futex_cancel()`\u0027s unguarded `futex_unqueue(\u0026ifd-\u003eq)` operate on attacker-reclaimed memory. This is the classic io_uring UAF/type-confusion shape that is leveraged into arbitrary write and local privilege escalation, which is why ZDI reported it.\nA:H - Dereferencing the freed `io_futex_data` as an `io_poll` reliably produces slab corruption, KASAN splats, and kernel oopses/panics even without a successful exploit. Any unprivileged user can repeat the trigger at will to crash the machine."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:04:39.909Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d9f93172820a53ab42c4b0e5e65291f4f9d00ad2"
        },
        {
          "url": "https://git.kernel.org/stable/c/d34c04152df517c59979b4bf2a47f491e06d3256"
        },
        {
          "url": "https://git.kernel.org/stable/c/508c1314b342b78591f51c4b5dadee31a88335df"
        },
        {
          "url": "https://www.zerodayinitiative.com/advisories/ZDI-25-915/"
        }
      ],
      "title": "io_uring/futex: ensure io_futex_wait() cleans up properly on failure",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-39698",
    "datePublished": "2025-09-05T17:21:04.360Z",
    "dateReserved": "2025-04-16T07:20:57.115Z",
    "dateUpdated": "2026-08-05T12:04:39.909Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}