{"dataType": "CVE_RECORD", "dataVersion": "5.1", "cveMetadata": {"cveId": "CVE-2025-39977", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.150Z", "datePublished": "2025-10-15T07:55:58.283Z", "dateUpdated": "2025-10-15T07:55:58.283Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2025-10-15T07:55:58.283Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Prevent use-after-free during requeue-PI\n\nsyzbot managed to trigger the following race:\n\n T1 T2\n\n futex_wait_requeue_pi()\n futex_do_wait()\n schedule()\n futex_requeue()\n futex_proxy_trylock_atomic()\n futex_requeue_pi_prepare()\n requeue_pi_wake_futex()\n futex_requeue_pi_complete()\n /* preempt */\n\n * timeout/ signal wakes T1 *\n\n futex_requeue_pi_wakeup_sync() // Q_REQUEUE_PI_LOCKED\n futex_hash_put()\n // back to userland, on stack futex_q is garbage\n\n /* back */\n wake_up_state(q->task, TASK_NORMAL);\n\nIn this scenario futex_wait_requeue_pi() is able to leave without using\nfutex_q::lock_ptr for synchronization.\n\nThis can be prevented by reading futex_q::task before updating the\nfutex_q::requeue_state. A reference on the task_struct is not needed\nbecause requeue_pi_wake_futex() is invoked with a spinlock_t held which\nimplies a RCU read section.\n\nEven if T1 terminates immediately after, the task_struct will remain valid\nduring T2's wake_up_state(). A READ_ONCE on futex_q::task before\nfutex_requeue_pi_complete() is enough because it ensures that the variable\nis read before the state is updated.\n\nRead futex_q::task before updating the requeue state, use it for the\nfollowing wakeup."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/futex/requeue.c"], "versions": [{"version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8", "lessThan": "cb5d19a61274b51b49601214a87af573b43d60fa", "status": "affected", "versionType": "git"}, {"version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8", "lessThan": "348736955ed6ca6e99ca24b93b1d3fbfe352c181", "status": "affected", "versionType": "git"}, {"version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8", "lessThan": "a170b9c0dde83312b8b58ccc91509c7c15711641", "status": "affected", "versionType": "git"}, {"version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8", "lessThan": "d824b2dbdcfe3c390278dd9652ea526168ef6850", "status": "affected", "versionType": "git"}, {"version": "07d91ef510fb16a2e0ca7453222105835b7ba3b8", "lessThan": "b549113738e8c751b613118032a724b772aa83f2", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/futex/requeue.c"], "versions": [{"version": "5.15", "status": "affected"}, {"version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.155", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.109", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.50", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.16.10", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.17", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.1.155"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.16.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.17"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/cb5d19a61274b51b49601214a87af573b43d60fa"}, {"url": "https://git.kernel.org/stable/c/348736955ed6ca6e99ca24b93b1d3fbfe352c181"}, {"url": "https://git.kernel.org/stable/c/a170b9c0dde83312b8b58ccc91509c7c15711641"}, {"url": "https://git.kernel.org/stable/c/d824b2dbdcfe3c390278dd9652ea526168ef6850"}, {"url": "https://git.kernel.org/stable/c/b549113738e8c751b613118032a724b772aa83f2"}], "title": "futex: Prevent use-after-free during requeue-PI", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Prevent use-after-free during requeue-PI\n\nsyzbot managed to trigger the following race:\n\n T1 T2\n\n futex_wait_requeue_pi()\n futex_do_wait()\n schedule()\n futex_requeue()\n futex_proxy_trylock_atomic()\n futex_requeue_pi_prepare()\n requeue_pi_wake_futex()\n futex_requeue_pi_complete()\n /* preempt */\n\n * timeout/ signal wakes T1 *\n\n futex_requeue_pi_wakeup_sync() // Q_REQUEUE_PI_LOCKED\n futex_hash_put()\n // back to userland, on stack futex_q is garbage\n\n /* back */\n wake_up_state(q->task, TASK_NORMAL);\n\nIn this scenario futex_wait_requeue_pi() is able to leave without using\nfutex_q::lock_ptr for synchronization.\n\nThis can be prevented by reading futex_q::task before updating the\nfutex_q::requeue_state. A reference on the task_struct is not needed\nbecause requeue_pi_wake_futex() is invoked with a spinlock_t held which\nimplies a RCU read section.\n\nEven if T1 terminates immediately after, the task_struct will remain valid\nduring T2's wake_up_state(). A READ_ONCE on futex_q::task before\nfutex_requeue_pi_complete() is enough because it ensures that the variable\nis read before the state is updated.\n\nRead futex_q::task before updating the requeue state, use it for the\nfollowing wakeup."}], "id": "CVE-2025-39977", "lastModified": "2025-10-16T15:29:11.563", "metrics": {}, "published": "2025-10-15T08:15:35.517", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/348736955ed6ca6e99ca24b93b1d3fbfe352c181"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a170b9c0dde83312b8b58ccc91509c7c15711641"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b549113738e8c751b613118032a724b772aa83f2"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/cb5d19a61274b51b49601214a87af573b43d60fa"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d824b2dbdcfe3c390278dd9652ea526168ef6850"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis"}

{"bugzilla": {"description": "kernel: futex: Prevent use-after-free during requeue-PI", "id": "2404113", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2404113"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "details": ["In the Linux kernel, the following vulnerability has been resolved:\nfutex: Prevent use-after-free during requeue-PI\nsyzbot managed to trigger the following race:\nT1 T2\nfutex_wait_requeue_pi()\nfutex_do_wait()\nschedule()\nfutex_requeue()\nfutex_proxy_trylock_atomic()\nfutex_requeue_pi_prepare()\nrequeue_pi_wake_futex()\nfutex_requeue_pi_complete()\n/* preempt */\n* timeout/ signal wakes T1 *\nfutex_requeue_pi_wakeup_sync() // Q_REQUEUE_PI_LOCKED\nfutex_hash_put()\n// back to userland, on stack futex_q is garbage\n/* back */\nwake_up_state(q->task, TASK_NORMAL);\nIn this scenario futex_wait_requeue_pi() is able to leave without using\nfutex_q::lock_ptr for synchronization.\nThis can be prevented by reading futex_q::task before updating the\nfutex_q::requeue_state. A reference on the task_struct is not needed\nbecause requeue_pi_wake_futex() is invoked with a spinlock_t held which\nimplies a RCU read section.\nEven if T1 terminates immediately after, the task_struct will remain valid\nduring T2's wake_up_state(). A READ_ONCE on futex_q::task before\nfutex_requeue_pi_complete() is enough because it ensures that the variable\nis read before the state is updated.\nRead futex_q::task before updating the requeue state, use it for the\nfollowing wakeup."], "name": "CVE-2025-39977", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2025-10-15T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-39977\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-39977\nhttps://lore.kernel.org/linux-cve-announce/2025101558-CVE-2025-39977-b3a2@gregkh/T"], "threat_severity": "Moderate"}