{"api_version":"1","generated_at":"2026-10-24T15:26:43+00:00","cve":"CVE-2026-89548","urls":{"html":"https://cve.report/CVE-2026-89548","api":"https://cve.report/api/cve/CVE-2026-89548.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89548","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89548"},"summary":{"title":"SUNRPC: always drain cache_cleaner before destroying a cache_detail","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: always drain cache_cleaner before destroying a cache_detail\n\nsunrpc_destroy_cache_detail() only cancels the global cache_cleaner\ndelayed_work when cache_list is empty.  During per-netns teardown\ncache_list is never empty because init_net's caches remain registered,\nso the cancel never fires.  After unlink, the caller proceeds to\ncache_destroy_net() which kfrees the cache_detail while cache_clean()\nmay still hold a dangling pointer to it.  The result is a\nuse-after-free: cache_dequeue() takes cd->queue_lock on freed memory,\nand cache_put() dereferences cd->cache_put as a function pointer from\nfreed slab.\n\nDrop the list_empty guard so that cancel_delayed_work_sync() always\nruns, ensuring any in-flight cache_clean() completes before the\ncache_detail is freed.  Re-arm the cleaner afterwards if other caches\nare still registered.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:38","updated_at":"2026-10-19 09:17:49"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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"}}],"references":[{"url":"https://git.kernel.org/stable/c/6d74ecc2be120a0c300b224b7649fe93c0453714","name":"https://git.kernel.org/stable/c/6d74ecc2be120a0c300b224b7649fe93c0453714","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3d60fdf951143d6ef4e352e2f8eb852286701726","name":"https://git.kernel.org/stable/c/3d60fdf951143d6ef4e352e2f8eb852286701726","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cf239de7fdcc8336259b01ea4bcf650dadad1040","name":"https://git.kernel.org/stable/c/cf239de7fdcc8336259b01ea4bcf650dadad1040","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f42d0fda0c67695db6bc704b04b7c10240805377","name":"https://git.kernel.org/stable/c/f42d0fda0c67695db6bc704b04b7c10240805377","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2e861ce2aaa468351a6a47c4cbb4971ebb740c7b","name":"https://git.kernel.org/stable/c/2e861ce2aaa468351a6a47c4cbb4971ebb740c7b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dec787a15c96a5665e9ffc61b429a6a4ab26e6b9","name":"https://git.kernel.org/stable/c/dec787a15c96a5665e9ffc61b429a6a4ab26e6b9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5eea874a696201c31e7c2d7badbfa0d90e9961b5","name":"https://git.kernel.org/stable/c/5eea874a696201c31e7c2d7badbfa0d90e9961b5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9d44836f60c8c29bcdb1471fd9202387c642a890","name":"https://git.kernel.org/stable/c/9d44836f60c8c29bcdb1471fd9202387c642a890","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89548","name":"CVE 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the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: always drain cache_cleaner before destroying a cache_detail\n\nsunrpc_destroy_cache_detail() only cancels the global cache_cleaner\ndelayed_work when cache_list is empty.  During per-netns teardown\ncache_list is never empty because init_net's caches remain registered,\nso the cancel never fires.  After unlink, the caller proceeds to\ncache_destroy_net() which kfrees the cache_detail while cache_clean()\nmay still hold a dangling pointer to it.  The result is a\nuse-after-free: cache_dequeue() takes cd->queue_lock on freed memory,\nand cache_put() dereferences cd->cache_put as a function pointer from\nfreed slab.\n\nDrop the list_empty guard so that cancel_delayed_work_sync() always\nruns, ensuring any in-flight cache_clean() completes before the\ncache_detail is freed.  Re-arm the cleaner afterwards if other caches\nare still registered."}],"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 - sunrpc_destroy_cache_detail() runs from per-netns teardown (sunrpc_exit_net, nfsd_net_exit, gss_svc_shutdown_net) when a local task creates and destroys a network namespace; remote NFS/RPC traffic populates caches but never frees cache_detail.\nAC:L - The attacker controls both sides of the race: unshare of a user+net ns queues cache_cleaner at delay 0, writes expired entries via /proc/net/rpc/*/channel (ip_map_parse even calls cache_flush()), and drops the netns so destroy kfree()s cache_detail while cache_clean() still holds it.\nPR:L - Unprivileged users can create a user+network namespace (unshare -Urn). /proc/net/rpc cache files inherit userns-root ownership from proc_net_ns_init, so the attacker can populate and destroy those caches without init-namespace root.\nUI:N - The attacker creates the namespace, writes the cache channel, and tears the netns down from their own processes; no victim mount, file open, or other interaction is required.\nS:U - The use-after-free corrupts host kernel heap (struct cache_detail) within the same kernel security authority and is not a VM escape, IOMMU bypass, or other cross-boundary impact.\nC:H - cache_clean() calls cache_dequeue() and cache_put() on a kfree'd cache_detail; per kernel UAF guidance, reclaim of that slab object yields an arbitrary kernel read primitive.\nI:H - cache_put() invokes cd->cache_put from the freed slab as a function pointer, and cache_dequeue() takes cd->queue_lock on freed memory, giving a control-flow hijack/write primitive.\nA:H - Use-after-free of cache_detail (spinlock on freed queue_lock and an indirect call through freed cache_put) causes a kernel oops or panic even when not fully exploited for code execution."}]}],"providerMetadata":{"dateUpdated":"2026-10-19T08:48:41.057Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/dec787a15c96a5665e9ffc61b429a6a4ab26e6b9"},{"url":"https://git.kernel.org/stable/c/5eea874a696201c31e7c2d7badbfa0d90e9961b5"},{"url":"https://git.kernel.org/stable/c/cf239de7fdcc8336259b01ea4bcf650dadad1040"},{"url":"https://git.kernel.org/stable/c/6d74ecc2be120a0c300b224b7649fe93c0453714"},{"url":"https://git.kernel.org/stable/c/9d44836f60c8c29bcdb1471fd9202387c642a890"},{"url":"https://git.kernel.org/stable/c/2e861ce2aaa468351a6a47c4cbb4971ebb740c7b"},{"url":"https://git.kernel.org/stable/c/3d60fdf951143d6ef4e352e2f8eb852286701726"},{"url":"https://git.kernel.org/stable/c/f42d0fda0c67695db6bc704b04b7c10240805377"}],"title":"SUNRPC: always drain cache_cleaner before destroying a cache_detail","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89548","datePublished":"2026-09-11T19:44:23.298Z","dateReserved":"2026-09-11T19:38:34.723Z","dateUpdated":"2026-10-19T08:48:41.057Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:38","lastModifiedDate":"2026-10-19 09:17:49","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-16T19:23:39.938577Z","id":"CVE-2026-89548","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89548","Ordinal":"1","Title":"SUNRPC: always drain cache_cleaner before destroying a cache_det","CVE":"CVE-2026-89548","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89548","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: always drain cache_cleaner before destroying a cache_detail\n\nsunrpc_destroy_cache_detail() only cancels the global cache_cleaner\ndelayed_work when cache_list is empty.  During per-netns teardown\ncache_list is never empty because init_net's caches remain registered,\nso the cancel never fires.  After unlink, the caller proceeds to\ncache_destroy_net() which kfrees the cache_detail while cache_clean()\nmay still hold a dangling pointer to it.  The result is a\nuse-after-free: cache_dequeue() takes cd->queue_lock on freed memory,\nand cache_put() dereferences cd->cache_put as a function pointer from\nfreed slab.\n\nDrop the list_empty guard so that cancel_delayed_work_sync() always\nruns, ensuring any in-flight cache_clean() completes before the\ncache_detail is freed.  Re-arm the cleaner afterwards if other caches\nare still registered.","Type":"Description","Title":"SUNRPC: always drain cache_cleaner before destroying a cache_det"}]}}}