{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89547", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.722Z", "datePublished": "2026-09-11T19:44:22.644Z", "dateUpdated": "2026-10-19T08:48:38.898Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:48:38.898Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: Check svc pool percpu counter allocation\n\n__svc_create() initializes three per-pool percpu_counter stats and\nignores every return value. On SMP, percpu_counter_init() fails when\n__alloc_percpu_gfp() cannot satisfy the allocation, leaving the failed\ncounter with fbc->counters == NULL and its embedded raw_spinlock_t,\nlist_head, and count never initialized. __svc_create() returns the\nhalf-constructed svc_serv to nfsd, lockd, or the NFS callback service\nanyway.\n\nOnce that service is live, the hot-path increments in\nsvc_xprt_enqueue(), svc_handle_xprt(), and\nsvc_pool_wake_idle_thread() reach a counter whose backing pointer is\nNULL. The pointer is a per-cpu offset, so the access does not fault:\nit resolves to offset zero of the current CPU's per-cpu area and\nsilently corrupts whatever variable lives there. A\n/proc/fs/nfsd/pool_stats read walks the same NULL per-cpu storage and\nreturns garbage, and on CONFIG_DEBUG_SPINLOCK or lockdep it splats on\nthe never-initialized lock.\n\nCreating the broken service requires a percpu allocation failure during\nRPC server startup, so it is reachable only by a local administrator\nunder memory pressure or fault injection; a remote peer cannot induce\nthe bad state on its own.\n\nCheck each percpu_counter_init() return value in __svc_create() and\nfail when an allocation fails, unwinding the counters already set up\nin the current pool and in every pool initialized before it. A\ndiscrete percpu_counter_destroy() per counter at teardown frees each\nper-cpu allocation exactly once." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - After nfsd, lockd, or the NFS-callback SUNRPC service is created with a failed pool percpu_counter, svc_xprt_enqueue(), svc_handle_xprt(), and svc_pool_wake_idle_thread() increment those counters on the packet-receive hot path, so a remote NFS/NLM/callback peer triggers the corruption by sending RPC traffic (typically TCP/2049).\nAC:H - The broken service exists only if percpu_counter_init() fails inside __svc_create() during RPC server startup; that tiny per-CPU allocation failure requires memory pressure or fault injection that a remote peer cannot induce, so success depends on a startup condition the attacker cannot control.\nPR:N - svc_xprt_enqueue() and svc_handle_xprt() run when a SUNRPC transport has received data, before RPC authentication, so an unauthenticated network client needs no host account or capabilities to deliver the traffic that hits the NULL counters.\nUI:N - Exploitation is inbound RPC to an already-running nfsd, lockd, or NFS callback listener; no administrator or end-user action such as mounting a filesystem or opening a file is required at exploit time.\nS:U - Per-CPU corruption, pool_stats disclosure, and any resulting oops stay inside the host kernel's SUNRPC/nfsd authority and do not cross a VM, IOMMU, or other security boundary.\nC:H - A NULL fbc->counters pointer is treated as a per-CPU offset, so increments and percpu_counter_sum_positive() read offset 0 of each CPU's per-CPU area; world-readable nfsd pool_stats returns those values, giving a kernel-memory disclosure primitive from the same corruption.\nI:H - percpu_counter_inc() cmpxchg-increments and the batch-fold path later zeroes the s32 at per-CPU offset 0 via __this_cpu_sub(), silently corrupting whatever kernel per-CPU variable lives there and yielding a write primitive against that storage rather than a contained stats-only update.\nA:H - The never-initialized counter lock/lockdep map can splat under CONFIG_DEBUG_SPINLOCK or lockdep, and corrupting the CPU's per-CPU area can oops or panic the host, so the bug is a kernel crash/DoS even when not fully exploited." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sunrpc/svc.c" ], "versions": [ { "version": "ccf08bed6e7a80519569456edd2ea21b7b1701c6", "lessThan": "57ac7d899409b0a9b768cf417e3bb86bcca3d4c6", "status": "affected", "versionType": "git" }, { "version": "ccf08bed6e7a80519569456edd2ea21b7b1701c6", "lessThan": "3a2b7649de76376a69f1d3ed2a539fb15907cd4d", "status": "affected", "versionType": "git" }, { "version": "ccf08bed6e7a80519569456edd2ea21b7b1701c6", "lessThan": "bd1ef2cfb44d72b7aa6943e87b206eb0e30fbd0c", "status": "affected", "versionType": "git" }, { "version": "ccf08bed6e7a80519569456edd2ea21b7b1701c6", "lessThan": "b541a15046976e481618726cc23db0fb22d576db", "status": "affected", "versionType": "git" }, { "version": "ccf08bed6e7a80519569456edd2ea21b7b1701c6", "lessThan": "43e11e164704dde975c9edb370de1a06bec67270", "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/svc.c" ], "versions": [ { "version": "6.3", "status": "affected" }, { "version": "0", "lessThan": "6.3", "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", "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": "6.3", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/57ac7d899409b0a9b768cf417e3bb86bcca3d4c6" }, { "url": "https://git.kernel.org/stable/c/3a2b7649de76376a69f1d3ed2a539fb15907cd4d" }, { "url": "https://git.kernel.org/stable/c/bd1ef2cfb44d72b7aa6943e87b206eb0e30fbd0c" }, { "url": "https://git.kernel.org/stable/c/b541a15046976e481618726cc23db0fb22d576db" }, { "url": "https://git.kernel.org/stable/c/43e11e164704dde975c9edb370de1a06bec67270" } ], "title": "SUNRPC: Check svc pool percpu counter allocation", "x_generator": { "engine": "bippy-1.2.0" } } } }