{"schema":"threatline.record/2","record":{"id":"CVE-2026-98464","aliases":[],"summary":"RISC-V: KVM: Synchronize hrtimer callback during teardown","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nRISC-V: KVM: Synchronize hrtimer callback during teardown\n\nThe non-Sstc hrtimer callback clears next_set before its final uses of\nthe enclosing vCPU.  If teardown observes next_set as false while the\ncallback is still running, kvm_riscv_vcpu_timer_cancel() skips\nhrtimer_cancel() and kvm_destroy_vcpus() can free the vCPU before the\ncallback enters kvm_riscv_vcpu_set_interrupt().\n\nA guest can arm the timer with SBI TIME and request shutdown with SBI\nlegacy shutdown or SRST.  A VMM that honors KVM_EXIT_SYSTEM_EVENT and\ndestroys the VM supplies the teardown side of the race; no post-launch\nhost ioctl is needed to arm or request teardown.\n\nOn upstream master 62cc90241548, generic KASAN reported:\n\n  BUG: KASAN: slab-use-after-free in do_raw_spin_lock\n  Write of size 4 at addr ff60000005e58898\n\n  kvm_riscv_vcpu_set_interrupt\n  kvm_riscv_vcpu_hrtimer_expired\n  __hrtimer_run_queues\n  hrtimer_interrupt\n\nThe object was allocated by KVM_CREATE_VCPU and freed concurrently by:\n\n  kvm_destroy_vcpus\n  kvm_arch_destroy_vm\n  kvm_destroy_vm\n  __fput\n\nFor deterministic validation, I added mdelay(1000) immediately after\nthe existing next_set = false assignment.  This only widens the\nexisting post-clear callback window.  A no-delay trace build naturally\nreached the callback-after-teardown-start/before-deinit ordering in 12\nof 200 runs, but 1,500 stock-kernel stress iterations did not produce a\nKASAN report, so natural reproduction is timing-sensitive.\n\nAlways invoke hrtimer_cancel() for an initialized timer.  Preserve the\nexisting -EINVAL result when the timer is no longer set, but only after\nsynchronizing with a running callback.\n\nWith this patch, hrtimer_cancel() blocked for the full widened callback\nwindow before vCPU destruction.  KASAN reported no error in 100\nfixed-and-widened runs or 200 fix-only timing-sweep runs.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98464","source_modified_at":"2026-10-24T14:08:56.354Z","fetched_at":"2026-10-24T14:26:37.433577Z","product":"Linux","vendor":"Linux","versions":[{"version":"3a9f66cb25e18a3eeca36c08d9f823a35b3ddc22","lessThan":"9bdbae64ae0dab93041ebc57ec4e93def793fc2d","status":"affected","versionType":"git"},{"version":"3a9f66cb25e18a3eeca36c08d9f823a35b3ddc22","lessThan":"2af03b606aadaaeb386658ef798c79bdcdef87c1","status":"affected","versionType":"git"},{"version":"3a9f66cb25e18a3eeca36c08d9f823a35b3ddc22","lessThan":"e66aced74f0122380603c9910a71d77618b28f0e","status":"affected","versionType":"git"},{"version":"3a9f66cb25e18a3eeca36c08d9f823a35b3ddc22","lessThan":"ea91f05a55b807ead3166546a2c75f4185ca645f","status":"affected","versionType":"git"},{"version":"3a9f66cb25e18a3eeca36c08d9f823a35b3ddc22","lessThan":"3cc6184bd5920c9685d87f4e260568feba08650d","status":"affected","versionType":"git"},{"version":"3a9f66cb25e18a3eeca36c08d9f823a35b3ddc22","lessThan":"aaad136d56d91252517272b68cd533e5714698d5","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98464","source_modified_at":"2026-10-24T14:08:56.354Z","fetched_at":"2026-10-24T14:26:37.433577Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.16","status":"affected"},{"version":"0","lessThan":"5.16","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.55","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.9","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98464","source_modified_at":"2026-10-24T14:08:56.354Z","fetched_at":"2026-10-24T14:26:37.433577Z","package":{"name":"Linux","ecosystem":null},"version":"9bdbae64ae0dab93041ebc57ec4e93def793fc2d","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98464","source_modified_at":"2026-10-24T14:08:56.354Z","fetched_at":"2026-10-24T14:26:37.433577Z","package":{"name":"Linux","ecosystem":null},"version":"2af03b606aadaaeb386658ef798c79bdcdef87c1","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98464","source_modified_at":"2026-10-24T14:08:56.354Z","fetched_at":"2026-10-24T14:26:37.433577Z","package":{"name":"Linux","ecosystem":null},"version":"3cc6184bd5920c9685d87f4e260568feba08650d","basis":"first unaffected version stated in the CVE record"}],"cvss":9.3,"severity":"Critical","kev":{"listed":false},"epss":{"probability":0.00172,"percentile":0.06316,"score_date":"2026-10-23"},"published_at":"2026-10-18T15:15:16.624Z","modified_at":"2026-10-24T14:08:56.354Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98464","fetched_at":"2026-10-24T14:26:37.433577Z","source_modified_at":"2026-10-24T14:08:56.354Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98464","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/9bdbae64ae0dab93041ebc57ec4e93def793fc2d"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/2af03b606aadaaeb386658ef798c79bdcdef87c1"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/e66aced74f0122380603c9910a71d77618b28f0e"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/ea91f05a55b807ead3166546a2c75f4185ca645f"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/3cc6184bd5920c9685d87f4e260568feba08650d"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/aaad136d56d91252517272b68cd533e5714698d5"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-24T14:08:56.354Z","content_hash":"81b84437cc692a629dcbc99e093452d1592024b70e3595ce60268a495c324083"}}