CVE-2026-90003 (GCVE-0-2026-90003)
Vulnerability from cvelistv5
Published
2026-09-16 10:33
Modified
2026-10-19 08:56
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: 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->task before futex_requeue_pi_complete() and wakes the waiter via wake_up_state(). This wake is intended to wake the waiter from its futex_do_wait() sleep. If the waiter is still sleeping there, it can not get into the Q_REQUEUE_PI_WAIT state (and require this removed wake). Should the waiter be woken up from futex_do_wait() by other means (as in this example) and sleep in futex_requeue_pi_wakeup_sync() then the wake_up_state() from requeue_pi_wake_futex() will wake it, too. Should the waiter task terminate before wake_up_state() had a chance to wake the task then the task pointer does not become invalid because the futex_hash_bucket::lock is held and the task pointer is RCU protected. [bigeasy: Updated comment and commit message]
References
Impacted products
Vendor Product Version
Linux Linux Version: 07d91ef510fb16a2e0ca7453222105835b7ba3b8
Version: 07d91ef510fb16a2e0ca7453222105835b7ba3b8
Version: 07d91ef510fb16a2e0ca7453222105835b7ba3b8
Version: 07d91ef510fb16a2e0ca7453222105835b7ba3b8
Version: 07d91ef510fb16a2e0ca7453222105835b7ba3b8
Version: 07d91ef510fb16a2e0ca7453222105835b7ba3b8
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/futex/requeue.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "220ee9e04ca3b7f014c000264aa6c884f036c86e",
              "status": "affected",
              "version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8",
              "versionType": "git"
            },
            {
              "lessThan": "81aadbd09bf1dcd3238212f336ba699503557ae8",
              "status": "affected",
              "version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8",
              "versionType": "git"
            },
            {
              "lessThan": "244f301759fd34b1dd0b4192ce44f8ef224e027d",
              "status": "affected",
              "version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8",
              "versionType": "git"
            },
            {
              "lessThan": "7d1559126d86be6e4f6a85663dfbfe85caa47e37",
              "status": "affected",
              "version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8",
              "versionType": "git"
            },
            {
              "lessThan": "e4a4ccfa470f910b747b3ee8d18670ed8ac8a236",
              "status": "affected",
              "version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8",
              "versionType": "git"
            },
            {
              "lessThan": "a3b8d46fe401cba3a5c46dea610e6eb3dc15370e",
              "status": "affected",
              "version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/futex/requeue.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Prevent rcuwait use-after-free during requeue PI\n\nOn PREEMPT_RT, FUTEX_CMP_REQUEUE_PI can trigger a KASAN report\n(slab-out-of-bounds) in futex_requeue_pi_complete() invocation of\nrcuwait_wake_up().\n\nThe futex_q used by futex_wait_requeue_pi() is allocated on the waiter\u0027s\nstack. An early wakeup can race with a PI requeue as follows:\n\n        waiter                          requeue task\n        ------                          ------------\nfutex_wait_requeue_pi()\n  futex_do_wait()\n    schedule()\n                                       futex_requeue\n                                         futex_proxy_trylock_atomic()\n                                           futex_requeue_pi_prepare()\n                                            Q_REQUEUE_PI_NONE -\u003e Q_REQUEUE_PI_IN_PROGRESS\n* timeout/ signal wakes waiter *\n  futex_requeue_pi_wakeup_sync()\n   Q_REQUEUE_PI_IN_PROGRESS -\u003e Q_REQUEUE_PI_WAIT\n                                           requeue_pi_wake_futex\n                                             futex_requeue_pi_complete()\n                                               cmpxchg Q_REQUEUE_PI_WAIT -\u003e Q_REQUEUE_PI_LOCKED\n    rcuwait_wait_event()\n      if (atomic_read(\u0026q-\u003erequeue_state) != Q_REQUEUE_PI_WAIT)\n       break /* no schedule() */\n\n /* q.pi_state-\u003eowner == current */\n futex_private_hash_put()\n /* return from syscall */\n                                              rcuwait_wake_up(\u0026q-\u003erequeue_wait)\n                                                /* q is gone */\n\nfutex_requeue_pi_complete() publishes Q_REQUEUE_PI_LOCKED before\ncalling rcuwait_wake_up(). The waiter observes this state in\nrcuwait_wait_event() before invoking schedule() in rcuwait_wait_event().\nHere, the waiter is free leave the syscall before requeue task can\ncomplete the wake.\n\nTo address this race skip rcuwait_wake_up() in the Q_REQUEUE_PI_LOCKED\ncase.\nThis state is only published by requeue_pi_wake_futex(), which saves\nq-\u003etask before futex_requeue_pi_complete() and wakes the waiter via\nwake_up_state().\n\nThis wake is intended to wake the waiter from its futex_do_wait() sleep.\nIf the waiter is still sleeping there, it can not get into the\nQ_REQUEUE_PI_WAIT state (and require this removed wake).\nShould the waiter be woken up from futex_do_wait() by other means (as in\nthis example) and sleep in futex_requeue_pi_wakeup_sync() then the\nwake_up_state() from requeue_pi_wake_futex() will wake it, too.\nShould the waiter task terminate before wake_up_state() had a chance to\nwake the task then the task pointer does not become invalid because the\nfutex_hash_bucket::lock is held and the task pointer is RCU protected.\n\n[bigeasy: Updated comment and commit message]"
        }
      ],
      "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 bug is reached only through the local futex(2) syscalls FUTEX_WAIT_REQUEUE_PI and FUTEX_CMP_REQUEUE_PI into kernel/futex/requeue.c; there is no network, Bluetooth, or physical-device path.\nAC:L - The attacker controls both sides of the race: a waiter thread using FUTEX_WAIT_REQUEUE_PI with an attacker-chosen timeout or signal, and a concurrent FUTEX_CMP_REQUEUE_PI from another thread, and can retry with CPU pinning until the waiter returns before rcuwait_wake_up() on PREEMPT_RT.\nPR:L - Any unprivileged local user can invoke futex() with FUTEX_WAIT_REQUEUE_PI and FUTEX_CMP_REQUEUE_PI; do_futex() and futex_requeue() perform no capability or credential checks, CONFIG_FUTEX_PI is default-y, and the path is reachable from containers without elevated privileges.\nUI:N - The attacker\u0027s own threads perform the wait, timeout or signal, and PI requeue; no victim action such as mounting a filesystem or opening a file is required.\nS:U - The use-after-free corrupts kernel memory (the waiter\u0027s stack-allocated futex_q and a type-confused task_struct) within the same kernel security authority; this is a standard local privilege-escalation issue, not a VM, IOMMU, or hypervisor escape.\nC:H - This is a use-after-free of the waiter\u0027s stack-allocated futex_q.requeue_wait; rcuwait_wake_up() reads a stale, attacker-refilled task_struct pointer and dereferences it in try_to_wake_up(), enabling arbitrary kernel-memory disclosure.\nI:H - The stale futex_q lives on the attacker\u0027s own kernel stack, which a following syscall can refill with controlled bytes, so rcuwait_wake_up() passes an attacker-chosen pointer into try_to_wake_up(), which writes task state and makes indirect scheduler calls, enabling privilege escalation.\nA:H - In the unexploited case, rcuwait_wake_up() dereferences a wild pointer from reused stack memory and causes a kernel oops or panic; any use-after-free of this kind is a High availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:56:17.256Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/220ee9e04ca3b7f014c000264aa6c884f036c86e"
        },
        {
          "url": "https://git.kernel.org/stable/c/81aadbd09bf1dcd3238212f336ba699503557ae8"
        },
        {
          "url": "https://git.kernel.org/stable/c/244f301759fd34b1dd0b4192ce44f8ef224e027d"
        },
        {
          "url": "https://git.kernel.org/stable/c/7d1559126d86be6e4f6a85663dfbfe85caa47e37"
        },
        {
          "url": "https://git.kernel.org/stable/c/e4a4ccfa470f910b747b3ee8d18670ed8ac8a236"
        },
        {
          "url": "https://git.kernel.org/stable/c/a3b8d46fe401cba3a5c46dea610e6eb3dc15370e"
        }
      ],
      "title": "futex: Prevent rcuwait use-after-free during requeue PI",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90003",
    "datePublished": "2026-09-16T10:33:13.420Z",
    "dateReserved": "2026-09-11T19:38:34.780Z",
    "dateUpdated": "2026-10-19T08:56:17.256Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.