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CVE-2026-89547 (GCVE-0-2026-89547)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:44 – Updated: 2026-09-14 12:00
VLAI
Title
SUNRPC: Check svc pool percpu counter allocation
Summary
In the Linux kernel, the following vulnerability has been resolved: SUNRPC: Check svc pool percpu counter allocation __svc_create() initializes three per-pool percpu_counter stats and ignores every return value. On SMP, percpu_counter_init() fails when __alloc_percpu_gfp() cannot satisfy the allocation, leaving the failed counter with fbc->counters == NULL and its embedded raw_spinlock_t, list_head, and count never initialized. __svc_create() returns the half-constructed svc_serv to nfsd, lockd, or the NFS callback service anyway. Once that service is live, the hot-path increments in svc_xprt_enqueue(), svc_handle_xprt(), and svc_pool_wake_idle_thread() reach a counter whose backing pointer is NULL. The pointer is a per-cpu offset, so the access does not fault: it resolves to offset zero of the current CPU's per-cpu area and silently corrupts whatever variable lives there. A /proc/fs/nfsd/pool_stats read walks the same NULL per-cpu storage and returns garbage, and on CONFIG_DEBUG_SPINLOCK or lockdep it splats on the never-initialized lock. Creating the broken service requires a percpu allocation failure during RPC server startup, so it is reachable only by a local administrator under memory pressure or fault injection; a remote peer cannot induce the bad state on its own. Check each percpu_counter_init() return value in __svc_create() and fail when an allocation fails, unwinding the counters already set up in the current pool and in every pool initialized before it. A discrete percpu_counter_destroy() per counter at teardown frees each per-cpu allocation exactly once.
Severity
8.1 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: ccf08bed6e7a80519569456edd2ea21b7b1701c6 , < 57ac7d899409b0a9b768cf417e3bb86bcca3d4c6 (git)
Affected: ccf08bed6e7a80519569456edd2ea21b7b1701c6 , < 3a2b7649de76376a69f1d3ed2a539fb15907cd4d (git)
Affected: ccf08bed6e7a80519569456edd2ea21b7b1701c6 , < bd1ef2cfb44d72b7aa6943e87b206eb0e30fbd0c (git)
Affected: ccf08bed6e7a80519569456edd2ea21b7b1701c6 , < b541a15046976e481618726cc23db0fb22d576db (git)
Affected: ccf08bed6e7a80519569456edd2ea21b7b1701c6 , < 43e11e164704dde975c9edb370de1a06bec67270 (git)
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Linux Linux Affected: 6.3
Unaffected: 0 , < 6.3 (semver)
Unaffected: 6.6.157 , ≤ 6.6.* (semver)
Unaffected: 6.12.109 , ≤ 6.12.* (semver)
Unaffected: 6.18.50 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
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      "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-\u003ecounters == 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\u0027s 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": [
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
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              "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\u0027s SUNRPC/nfsd authority and do not cross a VM, IOMMU, or other security boundary.\nC:H - A NULL fbc-\u003ecounters pointer is treated as a per-CPU offset, so increments and percpu_counter_sum_positive() read offset 0 of each CPU\u0027s 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\u0027s per-CPU area can oops or panic the host, so the bug is a kernel crash/DoS even when not fully exploited."
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        "shortName": "Linux"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89547",
    "datePublished": "2026-09-11T19:44:22.644Z",
    "dateReserved": "2026-09-11T19:38:34.722Z",
    "dateUpdated": "2026-09-14T12:00:50.421Z",
    "state": "PUBLISHED"
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      "date": "2026-09-16",
      "epss": "0.00568",
      "percentile": "0.45577"
    },
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      "initial_release_date": "2026-09-13T01:03:00.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "SUNRPC: Check svc pool percpu counter allocation",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89547.json",
      "version": "2"
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On SMP, percpu_counter_init() fails when\\n__alloc_percpu_gfp() cannot satisfy the allocation, leaving the failed\\ncounter with fbc-\u003ecounters == 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\u0027s 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.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/sunrpc/svc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"ccf08bed6e7a80519569456edd2ea21b7b1701c6\",\"lessThan\":\"57ac7d899409b0a9b768cf417e3bb86bcca3d4c6\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ccf08bed6e7a80519569456edd2ea21b7b1701c6\",\"lessThan\":\"3a2b7649de76376a69f1d3ed2a539fb15907cd4d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ccf08bed6e7a80519569456edd2ea21b7b1701c6\",\"lessThan\":\"bd1ef2cfb44d72b7aa6943e87b206eb0e30fbd0c\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ccf08bed6e7a80519569456edd2ea21b7b1701c6\",\"lessThan\":\"b541a15046976e481618726cc23db0fb22d576db\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ccf08bed6e7a80519569456edd2ea21b7b1701c6\",\"lessThan\":\"43e11e164704dde975c9edb370de1a06bec67270\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/sunrpc/svc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.3\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.3\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.157\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.109\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.50\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"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\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.2,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/3a2b7649de76376a69f1d3ed2a539fb15907cd4d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/43e11e164704dde975c9edb370de1a06bec67270\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/57ac7d899409b0a9b768cf417e3bb86bcca3d4c6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b541a15046976e481618726cc23db0fb22d576db\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/bd1ef2cfb44d72b7aa6943e87b206eb0e30fbd0c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-14T15:20:44+00:00",
      "cve": "CVE-2026-89547",
      "id": "CVE-2026-89547",
      "initial_release_date": "2026-09-11T00:00:00+00:00",
      "product_status:known_affected": "199",
      "product_status:known_not_affected": "77",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: SUNRPC: Check svc pool percpu counter allocation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89547.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-16T00:02:08Z",
      "cve": "CVE-2026-89547",
      "id": "CVE-2026-89547",
      "initial_release_date": "2026-09-12T16:26:15Z",
      "product_status:known_affected": "114",
      "product_status:known_not_affected": "239",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89547",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89547.json",
      "version": "4"
    }
  }
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
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