{"id":"CVE-2026-89547","title":"SUNRPC: Check svc pool percpu counter allocation","summary":"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_…","severity":"high","cvss":8.1,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-476"],"vendor":"Linux","product":"Linux","affected":["Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < 57ac7d899409b0a9b768cf417e3bb86bcca3d4c6","Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < 3a2b7649de76376a69f1d3ed2a539fb15907cd4d","Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < bd1ef2cfb44d72b7aa6943e87b206eb0e30fbd0c","Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < b541a15046976e481618726cc23db0fb22d576db","Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < 43e11e164704dde975c9edb370de1a06bec67270","Linux 6.3"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:48:38.898Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89547","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"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89547.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89547"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532039"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89547"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89547"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89547.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00561,"epssPercentile":0.46468,"scores":{"cna":8.1,"vendor":7},"ingestedAt":"2026-09-14T15:23:07.452Z","slug":"CVE-2026-89547","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < 57ac7d899409b0a9b768cf417e3bb86bcca3d4c6`\n- `Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < 3a2b7649de76376a69f1d3ed2a539fb15907cd4d`\n- `Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < bd1ef2cfb44d72b7aa6943e87b206eb0e30fbd0c`\n- `Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < b541a15046976e481618726cc23db0fb22d576db`\n- `Linux >= ccf08bed6e7a80519569456edd2ea21b7b1701c6 < 43e11e164704dde975c9edb370de1a06bec67270`\n- `Linux 6.3`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89547.json)","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":44.6,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":224714,"id":"CVE-2026-89547","ts":1792401492111,"field":"cvss","old":"7","new":"8.1"},{"seq":202753,"id":"CVE-2026-89547","ts":1789403715629,"field":"cvss","old":"8.1","new":"7"},{"seq":197941,"id":"CVE-2026-89547","ts":1789384321056,"field":"cvss","old":"4.7","new":"8.1"},{"seq":197940,"id":"CVE-2026-89547","ts":1789384321056,"field":"severity","old":"medium","new":"high"},{"seq":183483,"id":"CVE-2026-89547","ts":1789356675551,"field":"cvss","old":"8.1","new":"4.7"},{"seq":183482,"id":"CVE-2026-89547","ts":1789356675551,"field":"severity","old":"high","new":"medium"},{"seq":153350,"id":"CVE-2026-89547","ts":1789285350154,"field":"cvss","old":null,"new":"8.1"},{"seq":153349,"id":"CVE-2026-89547","ts":1789285350154,"field":"severity","old":"none","new":"high"},{"seq":109612,"id":"CVE-2026-89547","ts":1789183732643,"field":"cvss","old":null,"new":"4.7"},{"seq":109611,"id":"CVE-2026-89547","ts":1789183732643,"field":"severity","old":"none","new":"medium"}]}