CVE-2024-56709

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2024-56709", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-27T15:00:39.857Z", "datePublished": "2024-12-29T08:42:58.403Z", "dateUpdated": "2026-08-05T11:46:12.483Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:46:12.483Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: check if iowq is killed before queuing\n\ntask work can be executed after the task has gone through io_uring\ntermination, whether it's the final task_work run or the fallback path.\nIn this case, task work will find ->io_wq being already killed and\nnull'ed, which is a problem if it then tries to forward the request to\nio_queue_iowq(). Make io_queue_iowq() fail requests in this case.\n\nNote that it also checks PF_KTHREAD, because the user can first close\na DEFER_TASKRUN ring and shortly after kill the task, in which case\n->iowq check would race."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerability is reached purely through the io_uring syscall interface (io_uring_setup/io_uring_enter, SQE submission, and close(2) of the ring fd), which requires local access to the machine. Per kernel scoring guidance io_uring bugs are Local.\nAC:L - The attacker controls both sides of the race \u2014 they choose exactly when to close the DEFER_TASKRUN ring (driving the request into the PF_KTHREAD fallback worker) and when to exit the submitting task (driving io_wq_put_and_exit/kfree), and can retry the whole sequence in a fresh process arbitrarily many times. The NULL-io_wq/BUG_ON variant is essentially deterministic once the exit ordering is arranged.\nPR:L - Any unprivileged local user with default io_uring access can create the ring, submit an IOSQE_ASYNC/IOSQE_IO_DRAIN request (REQ_F_FORCE_ASYNC), and trigger the exit race; no capabilities, root, or user-namespace tricks are required.\nUI:N - The entire sequence is performed by the attacker's own process and threads with no victim action of any kind.\nS:U - The corruption and its consequences are confined to the Linux kernel's own security authority; there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - The freed struct io_wq is read back after kfree (wq->state, wq->acct[], wq->free_list, wq->task, wq->do_work/free_work), so an attacker who reclaims the kmalloc-1k slot obtains a use-after-free read primitive over kernel heap contents, and per guidance a UAF is scored High.\nI:H - io_run_cancel() invokes wq->do_work(work) and wq->free_work(work) \u2014 indirect calls through function pointers read from the freed, attacker-reclaimable allocation \u2014 and io_wq_insert_work() writes list pointers into that freed memory, giving control-flow hijack and write primitives suitable for privilege escalation.\nA:H - The NULL-io_wq path hits BUG_ON() for a guaranteed kernel oops (full panic with panic_on_oops), and because it fires inside io_fallback_req_func() while holding ctx->uring_lock the mutex is leaked, permanently hanging io_ring_exit_work and any task touching that ring; the UAF variant additionally crashes on freed memory."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["io_uring/io_uring.c"], "versions": [{"version": "773af69121ecc6c53d192661af8d53bb3db028ae", "lessThan": "534d59ab38010aada88390db65985e65d0de7d9e", "status": "affected", "versionType": "git"}, {"version": "773af69121ecc6c53d192661af8d53bb3db028ae", "lessThan": "2ca94c8de36091067b9ce7527ae8db3812d38781", "status": "affected", "versionType": "git"}, {"version": "773af69121ecc6c53d192661af8d53bb3db028ae", "lessThan": "4f95a2186b7f2af09331e1e8069bcaf34fe019cf", "status": "affected", "versionType": "git"}, {"version": "773af69121ecc6c53d192661af8d53bb3db028ae", "lessThan": "dbd2ca9367eb19bc5e269b8c58b0b1514ada9156", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["io_uring/io_uring.c"], "versions": [{"version": "5.14", "status": "affected"}, {"version": "0", "lessThan": "5.14", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.122", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.68", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.7", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.13", "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": "5.14", "versionEndExcluding": "6.1.122"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.6.68"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.12.7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.13"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/534d59ab38010aada88390db65985e65d0de7d9e"}, {"url": "https://git.kernel.org/stable/c/2ca94c8de36091067b9ce7527ae8db3812d38781"}, {"url": "https://git.kernel.org/stable/c/4f95a2186b7f2af09331e1e8069bcaf34fe019cf"}, {"url": "https://git.kernel.org/stable/c/dbd2ca9367eb19bc5e269b8c58b0b1514ada9156"}], "title": "io_uring: check if iowq is killed before queuing", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"title": "CVE Program Container", "references": [{"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T20:53:02.240Z"}}]}}

{}

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Make io_queue_iowq() fail requests in this case.\n\nNote that it also checks PF_KTHREAD, because the user can first close\na DEFER_TASKRUN ring and shortly after kill the task, in which case\n->iowq check would race."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: io_uring: comprueba si iowq se elimina antes de que se pueda ejecutar la tarea de cola work despu\u00e9s de que la tarea haya pasado por la terminaci\u00f3n io_uring, ya sea la ejecuci\u00f3n final de task_work o la ruta de respaldo. En este caso, la tarea work encontrar\u00e1 que ->io_wq ya se ha eliminado y se ha anulado, lo que es un problema si luego intenta reenviar la solicitud a io_queue_iowq(). Haz que io_queue_iowq() falle las solicitudes en este caso. Ten en cuenta que tambi\u00e9n comprueba PF_KTHREAD, porque el usuario puede cerrar primero un anillo DEFER_TASKRUN y poco despu\u00e9s eliminar la tarea, en cuyo caso la comprobaci\u00f3n de ->iowq se acelerar\u00eda."}], "id": "CVE-2024-56709", "lastModified": "2026-08-04T11:22:23.277", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2024-12-29T09:15:05.820", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/2ca94c8de36091067b9ce7527ae8db3812d38781"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/4f95a2186b7f2af09331e1e8069bcaf34fe019cf"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/534d59ab38010aada88390db65985e65d0de7d9e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/dbd2ca9367eb19bc5e269b8c58b0b1514ada9156"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: io_uring: check if iowq is killed before queuing", "id": "2334795", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2334795"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.4", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-362", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nio_uring: check if iowq is killed before queuing\ntask work can be executed after the task has gone through io_uring\ntermination, whether it's the final task_work run or the fallback path.\nIn this case, task work will find ->io_wq being already killed and\nnull'ed, which is a problem if it then tries to forward the request to\nio_queue_iowq(). Make io_queue_iowq() fail requests in this case.\nNote that it also checks PF_KTHREAD, because the user can first close\na DEFER_TASKRUN ring and shortly after kill the task, in which case\n->iowq check would race."], "name": "CVE-2024-56709", "package_state": [{"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": "Will not fix", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2024-12-29T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2024-56709\nhttps://nvd.nist.gov/vuln/detail/CVE-2024-56709\nhttps://lore.kernel.org/linux-cve-announce/2024122918-CVE-2024-56709-655c@gregkh/T"], "statement": "The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.\nFor the Red Hat Enterprise Linux 9 to confirm the current state, inspect the sysctl with the command:\ncat /proc/sys/kernel/unprivileged_bpf_disabled\nThe setting of 1 would mean that unprivileged users can not use eBPF, mitigating the flaw.", "threat_severity": "Moderate"}

{"created": "2025-07-13T11:21:49.902074+00:00", "updated": "2025-07-13T11:21:49.902127+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}