{"id":"CVE-2026-89545","state":"PUBLISHED","title":"sunrpc: defer rq_argp and rq_resp free until after RCU grace period","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: defer rq_argp and rq_resp free until after RCU grace period\n\nsvc_rqst_free() frees rqstp->rq_argp and rqstp->rq_resp synchronously\nvia kfree(), but defers the rqstp struct free via kfree_rcu().  After\nsvc_exit_thread() calls list_del_rcu() and svc_rqst_free(), there is\na window where RCU readers that started before list_del_rcu() can still\ntraverse the thread list and find the rqstp.  These readers (e.g.\nnfsd_nl_rpc_status_get_dumpit()) dereference rqstp->rq_argp, which has\nalready been freed — a use-after-free.\n\nFix this by moving the kfree of rq_argp and rq_resp into an explicit\ncall_rcu() callback alongside the struct free.  Resources not accessed\nby RCU readers (bvec, buffer pages, scratch folio, auth_data) remain\nsynchronously freed.","publishedAt":"2026-09-11T19:44:21.161Z","updatedAt":"2026-10-30T12:32:08.877Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"c977158237bccc3d2512d5b17c47ee3760dc8839","versionType":"git"},{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"0ea49d69aa806008b2424c8cf21cf746b9963967","versionType":"git"},{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"08bc49e0541260bf294962cf889a32a2d2713ad6","versionType":"git"},{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"e0c5693d3f9a5d4911735ab0e0eba4eecb1f1090","versionType":"git"},{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"c479bde671cbe2f9e152834a8b0eb7c3c295bbaf","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.19","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svc.c"]}],"references":["https://git.kernel.org/stable/c/c977158237bccc3d2512d5b17c47ee3760dc8839","https://git.kernel.org/stable/c/0ea49d69aa806008b2424c8cf21cf746b9963967","https://git.kernel.org/stable/c/08bc49e0541260bf294962cf889a32a2d2713ad6","https://git.kernel.org/stable/c/e0c5693d3f9a5d4911735ab0e0eba4eecb1f1090","https://git.kernel.org/stable/c/c479bde671cbe2f9e152834a8b0eb7c3c295bbaf"],"weaknesses":[],"ingestedAt":"2026-10-30T12:50:04.827Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/89xxx/CVE-2026-89545.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89545","state":"PUBLISHED","datePublished":"2026-09-11T19:44:21.161Z","dateUpdated":"2026-10-30T12:32:08.877Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.722Z"},"containers":{"cna":{"title":"sunrpc: defer rq_argp and rq_resp free until after RCU grace period","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: defer rq_argp and rq_resp free until after RCU grace period\n\nsvc_rqst_free() frees rqstp->rq_argp and rqstp->rq_resp synchronously\nvia kfree(), but defers the rqstp struct free via kfree_rcu().  After\nsvc_exit_thread() calls list_del_rcu() and svc_rqst_free(), there is\na window where RCU readers that started before list_del_rcu() can still\ntraverse the thread list and find the rqstp.  These readers (e.g.\nnfsd_nl_rpc_status_get_dumpit()) dereference rqstp->rq_argp, which has\nalready been freed — a use-after-free.\n\nFix this by moving the kfree of rq_argp and rq_resp into an explicit\ncall_rcu() callback alongside the struct free.  Resources not accessed\nby RCU readers (bvec, buffer pages, scratch folio, auth_data) remain\nsynchronously freed."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"c977158237bccc3d2512d5b17c47ee3760dc8839","versionType":"git"},{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"0ea49d69aa806008b2424c8cf21cf746b9963967","versionType":"git"},{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"08bc49e0541260bf294962cf889a32a2d2713ad6","versionType":"git"},{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"e0c5693d3f9a5d4911735ab0e0eba4eecb1f1090","versionType":"git"},{"version":"812443865c5fc255363d4a684a62c086af1addca","status":"affected","lessThan":"c479bde671cbe2f9e152834a8b0eb7c3c295bbaf","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.19","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svc.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c977158237bccc3d2512d5b17c47ee3760dc8839"},{"url":"https://git.kernel.org/stable/c/0ea49d69aa806008b2424c8cf21cf746b9963967"},{"url":"https://git.kernel.org/stable/c/08bc49e0541260bf294962cf889a32a2d2713ad6"},{"url":"https://git.kernel.org/stable/c/e0c5693d3f9a5d4911735ab0e0eba4eecb1f1090"},{"url":"https://git.kernel.org/stable/c/c479bde671cbe2f9e152834a8b0eb7c3c295bbaf"}],"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 - The use-after-free is reached by NFSD_CMD_RPC_STATUS_GET, a generic-netlink dump over AF_NETLINK that walks svc_rqst threads and reads rq_argp; remote NFS RPCs never enter nfsd_nl_rpc_status_get_dumpit().\nAC:L - The attacker fully controls the dumpit reader and can loop it while nfsd threads exit (dynamic idle-timeout kills or thread-count changes), and can further churn threads with NFS traffic; this is an attacker-driven RCU race, not a condition beyond their control.\nPR:L - NFSD_CMD_RPC_STATUS_GET is registered with GENL_CMD_CAP_DUMP and no GENL_ADMIN_PERM, so any unprivileged process in the nfsd network namespace can invoke the dump; exploiting it does not require CAP_NET_ADMIN or root.\nUI:N - The attacker issues the netlink dump themselves; no separate victim action such as mounting a filesystem or opening a device is required.\nS:U - This is a kernel-heap use-after-free in sunrpc/nfsd on the local host; impact stays inside the kernel's security authority and does not cross a VM, IOMMU, or other security boundary.\nC:H - dumpit dereferences the kfree'd rq_argp (nfsd4_compoundargs) and reads opcnt/opnums under rcu_read_lock; a kernel UAF with heap reuse of that object yields an arbitrary read primitive.\nI:H - The same slab UAF is heap-sprayable so a replaced rq_argp can make dumpit walk attacker-controlled args->ops[], enabling kernel memory corruption and control-flow hijacking.\nA:H - Use-after-free of rq_argp while an RCU reader still holds the svc_rqst from sp_all_threads can oops or panic the kernel even if the UAF is not fully turned into code execution."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:32:08.877Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-89545","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T19:23:36.292382Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T19:26:42.664Z"}}]}}}