futex: Prevent rcuwait use-after-free during requeue PI

{
  "id": "08dbe88ba60154fb292a4072ec36a3cd6f34f3b5dad225d179e3ef8c2b764b4b",
  "url": "https://osv.dev/vulnerability/CVE-2026-90003",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "futex: Prevent rcuwait use-after-free during requeue PI",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: futex: Prevent rcuwait use-after-free during requeue PI On PREEMPT_RT, FUTEX_CMP_REQUEUE_PI can trigger a KASAN report (slab-out-of-bounds) in futex_requeue_pi_complete() invocation of rcuwait_wake_up(). The futex_q used by futex_wait_requeue_pi() is allocated on the waiter's stack. An early wakeup can race with a PI requeue as follows: waiter requeue task ------ ------------ futex_wait_requeue_pi() futex_do_wait() schedule() futex_requeue futex_proxy_trylock_atomic() futex_requeue_pi_prepare() Q_REQUEUE_PI_NONE -> Q_REQUEUE_PI_IN_PROGRESS * timeout/ signal wakes waiter * futex_requeue_pi_wakeup_sync() Q_REQUEUE_PI_IN_PROGRESS -> Q_REQUEUE_PI_WAIT requeue_pi_wake_futex futex_requeue_pi_complete() cmpxchg Q_REQUEUE_PI_WAIT -> Q_REQUEUE_PI_LOCKED rcuwait_wait_event() if (atomic_read(&q->requeue_state) != Q_REQUEUE_PI_WAIT) break /* no schedule() */ /* q.pi_state->owner == current */ futex_private_hash_put() /* return from syscall */ rcuwait_wake_up(&q->requeue_wait) /* q is gone */ futex_requeue_pi_complete() publishes Q_REQUEUE_PI_LOCKED before calling rcuwait_wake_up(). The waiter observes this state in rcuwait_wait_event() before invoking schedule() in rcuwait_wait_event(). Here, the waiter is free leave the syscall before requeue task can complete the wake. To address this race skip rcuwait_wake_up() in the Q_REQUEUE_PI_LOCKED case. This state is only published by requeue_pi_wake_futex(), which saves q->tas",
    "evidence": "osv:CVE-2026-90003",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.188",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.110",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.51",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-90003",
      "aliases": [
        "CVE-2026-90003"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "07d91ef510fb16a2e0ca7453222105835b7ba3b8"
                },
                {
                  "fixed": "220ee9e04ca3b7f014c000264aa6c884f036c86e"
                },
                {
                  "fixed": "81aadbd09bf1dcd3238212f336ba699503557ae8"
                },
                {
                  "fixed": "244f301759fd34b1dd0b4192ce44f8ef224e027d"
                },
                {
                  "fixed": "7d1559126d86be6e4f6a85663dfbfe85caa47e37"
                },
                {
                  "fixed": "e4a4ccfa470f910b747b3ee8d18670ed8ac8a236"
                },
                {
                  "fixed": "a3b8d46fe401cba3a5c46dea610e6eb3dc15370e"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90003.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.15.0"
                },
                {
                  "fixed": "6.1.188"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.157"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.110"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.51"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90003.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.721070556Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/220ee9e04ca3b7f014c000264aa6c884f036c86e",
        "https://git.kernel.org/stable/c/244f301759fd34b1dd0b4192ce44f8ef224e027d",
        "https://git.kernel.org/stable/c/7d1559126d86be6e4f6a85663dfbfe85caa47e37",
        "https://git.kernel.org/stable/c/81aadbd09bf1dcd3238212f336ba699503557ae8",
        "https://git.kernel.org/stable/c/a3b8d46fe401cba3a5c46dea610e6eb3dc15370e",
        "https://git.kernel.org/stable/c/e4a4ccfa470f910b747b3ee8d18670ed8ac8a236",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90003.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90003",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90003.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90003",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505304,
  "published_at": "2026-09-16T10:33:13.42+00:00"
}