CVE-2026-89991

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89991", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.780Z", "datePublished": "2026-09-16T10:33:05.097Z", "dateUpdated": "2026-10-19T08:56:05.536Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:56:05.536Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix infinite loop in pcpu_freelist push with one possible CPU\n\n__pcpu_freelist_push() can loop forever when only one CPU is possible\nand an NMI re-enters pcpu_freelist_push() while the interrupted context\nholds that CPU's freelist lock.\n\nAfter the current-CPU fast path fails, the fallback loop walks\ncpu_possible_mask while skipping the current CPU. With CONFIG_SMP=n, or\nwhen an SMP kernel is limited to one possible CPU with nr_cpus=1 or\npossible_cpus=1, there are no other possible CPUs to examine. The loop\ntherefore makes no lock acquisition attempt and can never make progress.\n\nThe following stack was observed on a UP system:\n\n NMI context:\n pcpu_freelist_push\n free_htab_elem\n htab_map_delete_elem\n [perf-event BPF program]\n __perf_event_overflow\n perf_event_nmi_handler\n exc_nmi\n\n Interrupted context:\n __pcpu_freelist_push\n pcpu_freelist_push\n free_htab_elem\n htab_map_delete_elem\n [raw_tp/sys_enter BPF program]\n __bpf_trace_sys_enter\n do_syscall_64\n\nraw_res_spin_lock() detects the same-CPU recursive acquisition and\nreturns -EDEADLK, but the subsequent fallback loop has no candidate head\non a system with one possible CPU.\n\nRestore the extra fallback head that existed before the rqspinlock\nconversion. Keep the current-CPU fast path, then try the other possible\nCPUs and finally the extra head. The additional head lets a push, which\ncannot fail without losing a preallocated element, make progress when the\nonly per-CPU head is held by the interrupted context.\n\nAlso check the extra head from the pop path so that nodes placed there\ncan be reused."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/bpf/percpu_freelist.c", "kernel/bpf/percpu_freelist.h"], "versions": [{"version": "f2ac0e5d1c4dcc55d6510dcaefb8f45661a9a1fb", "lessThan": "a24a146ae2cb5d9faeea96d10010fcb6579abe1f", "status": "affected", "versionType": "git"}, {"version": "f2ac0e5d1c4dcc55d6510dcaefb8f45661a9a1fb", "lessThan": "a5b5e62baceff9e252c6535cf42a027d04f226cf", "status": "affected", "versionType": "git"}, {"version": "f2ac0e5d1c4dcc55d6510dcaefb8f45661a9a1fb", "lessThan": "efebf6496685c93150df5bb0794363ae70c5f58a", "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/bpf/percpu_freelist.c", "kernel/bpf/percpu_freelist.h"], "versions": [{"version": "6.15", "status": "affected"}, {"version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.5", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "6.15", "versionEndExcluding": "6.18.51"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.2.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/a24a146ae2cb5d9faeea96d10010fcb6579abe1f"}, {"url": "https://git.kernel.org/stable/c/a5b5e62baceff9e252c6535cf42a027d04f226cf"}, {"url": "https://git.kernel.org/stable/c/efebf6496685c93150df5bb0794363ae70c5f58a"}], "title": "bpf: Fix infinite loop in pcpu_freelist push with one possible CPU", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["kernel/bpf/percpu_freelist.c", "kernel/bpf/percpu_freelist.h"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "a24a146ae2cb5d9faeea96d10010fcb6579abe1f", "status": "affected", "version": "f2ac0e5d1c4dcc55d6510dcaefb8f45661a9a1fb", "versionType": "git"}, {"lessThan": "a5b5e62baceff9e252c6535cf42a027d04f226cf", "status": "affected", "version": "f2ac0e5d1c4dcc55d6510dcaefb8f45661a9a1fb", "versionType": "git"}, {"lessThan": "efebf6496685c93150df5bb0794363ae70c5f58a", "status": "affected", "version": "f2ac0e5d1c4dcc55d6510dcaefb8f45661a9a1fb", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["kernel/bpf/percpu_freelist.c", "kernel/bpf/percpu_freelist.h"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.15"}, {"lessThan": "6.15", "status": "unaffected", "version": "0", "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"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix infinite loop in pcpu_freelist push with one possible CPU\n\n__pcpu_freelist_push() can loop forever when only one CPU is possible\nand an NMI re-enters pcpu_freelist_push() while the interrupted context\nholds that CPU's freelist lock.\n\nAfter the current-CPU fast path fails, the fallback loop walks\ncpu_possible_mask while skipping the current CPU. With CONFIG_SMP=n, or\nwhen an SMP kernel is limited to one possible CPU with nr_cpus=1 or\npossible_cpus=1, there are no other possible CPUs to examine. The loop\ntherefore makes no lock acquisition attempt and can never make progress.\n\nThe following stack was observed on a UP system:\n\n NMI context:\n pcpu_freelist_push\n free_htab_elem\n htab_map_delete_elem\n [perf-event BPF program]\n __perf_event_overflow\n perf_event_nmi_handler\n exc_nmi\n\n Interrupted context:\n __pcpu_freelist_push\n pcpu_freelist_push\n free_htab_elem\n htab_map_delete_elem\n [raw_tp/sys_enter BPF program]\n __bpf_trace_sys_enter\n do_syscall_64\n\nraw_res_spin_lock() detects the same-CPU recursive acquisition and\nreturns -EDEADLK, but the subsequent fallback loop has no candidate head\non a system with one possible CPU.\n\nRestore the extra fallback head that existed before the rqspinlock\nconversion. Keep the current-CPU fast path, then try the other possible\nCPUs and finally the extra head. The additional head lets a push, which\ncannot fail without losing a preallocated element, make progress when the\nonly per-CPU head is held by the interrupted context.\n\nAlso check the extra head from the pop path so that nodes placed there\ncan be reused."}], "id": "CVE-2026-89991", "lastModified": "2026-10-19T09:18:46.253", "metrics": {}, "published": "2026-09-16T11:17:10.240", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a24a146ae2cb5d9faeea96d10010fcb6579abe1f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a5b5e62baceff9e252c6535cf42a027d04f226cf"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/efebf6496685c93150df5bb0794363ae70c5f58a"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f2ac0e5d1c4dcc55d6510dcaefb8f45661a9a1fb,a24a146ae2cb5d9faeea96d10010fcb6579abe1f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f2ac0e5d1c4dcc55d6510dcaefb8f45661a9a1fb,a5b5e62baceff9e252c6535cf42a027d04f226cf)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f2ac0e5d1c4dcc55d6510dcaefb8f45661a9a1fb,efebf6496685c93150df5bb0794363ae70c5f58a)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.15"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.15)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.51,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.5,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.3-rc2,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-17T15:30:19.751345+00:00", "updated": "2026-09-17T20:45:16.225158+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-758", "CWE-362"]}