{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89548","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.723Z","datePublished":"2026-09-11T19:44:23.298Z","dateUpdated":"2026-09-14T12:00:51.491Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-14T12:00:51.491Z"},"descriptions":[{"lang":"en","value":"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."}],"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 - 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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/cache.c"],"versions":[{"version":"820f9442e711a81749e70c40f149fc54c4ce0ca8","lessThan":"dec787a15c96a5665e9ffc61b429a6a4ab26e6b9","status":"affected","versionType":"git"},{"version":"820f9442e711a81749e70c40f149fc54c4ce0ca8","lessThan":"5eea874a696201c31e7c2d7badbfa0d90e9961b5","status":"affected","versionType":"git"},{"version":"820f9442e711a81749e70c40f149fc54c4ce0ca8","lessThan":"cf239de7fdcc8336259b01ea4bcf650dadad1040","status":"affected","versionType":"git"},{"version":"820f9442e711a81749e70c40f149fc54c4ce0ca8","lessThan":"6d74ecc2be120a0c300b224b7649fe93c0453714","status":"affected","versionType":"git"},{"version":"820f9442e711a81749e70c40f149fc54c4ce0ca8","lessThan":"9d44836f60c8c29bcdb1471fd9202387c642a890","status":"affected","versionType":"git"},{"version":"820f9442e711a81749e70c40f149fc54c4ce0ca8","lessThan":"2e861ce2aaa468351a6a47c4cbb4971ebb740c7b","status":"affected","versionType":"git"},{"version":"820f9442e711a81749e70c40f149fc54c4ce0ca8","lessThan":"3d60fdf951143d6ef4e352e2f8eb852286701726","status":"affected","versionType":"git"},{"version":"820f9442e711a81749e70c40f149fc54c4ce0ca8","lessThan":"f42d0fda0c67695db6bc704b04b7c10240805377","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/cache.c"],"versions":[{"version":"3.4","status":"affected"},{"version":"0","lessThan":"3.4","status":"unaffected","versionType":"semver"},{"version":"5.10.270","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.221","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.188","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.109","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.50","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.4","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","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":"3.4","versionEndExcluding":"5.10.270"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"7.3-rc1"}]}]}],"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"}}}}