{"id":"CVE-2025-68171","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/fpu: Ensure XFD state on signal delivery\n\nSean reported [1] the following splat when running KVM tests:\n\n   WARNING: CPU: 232 PID: 15391 at xfd_validate_state+0x65/…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/fpu: Ensure XFD state on signal delivery\n\nSean reported [1] the following splat when running KVM tests:\n\n   WARNING: CPU: 232 PID: 15391 at xfd_validate_state+0x65/…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","published":"2025-12-16","updated":"2026-10-14","sourceUpdated":"2026-10-14T13:10:00.187","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-68171","references":[{"url":"https://git.kernel.org/stable/c/1811c610653c0cd21cc9add14595b7cffaeca511","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/388eff894d6bc5f921e9bfff0e4b0ab2684a96e9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3f735419c4b43cde42e6d408db39137b82474e31","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5b2619b488f1d08b960c43c6468dd0759e8b3035","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/eefbfb722042fc9210d2e0ac2b063fd1abf51895","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00154,"epssPercentile":0.04047,"ingestedAt":"2026-10-14T13:30:58.443Z","slug":"CVE-2025-68171","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nx86/fpu: Ensure XFD state on signal delivery\n\nSean reported [1] the following splat when running KVM tests:\n\n   WARNING: CPU: 232 PID: 15391 at xfd_validate_state+0x65/0x70\n   Call Trace:\n    <TASK>\n    fpu__clear_user_states+0x9c/0x100\n    arch_do_signal_or_restart+0x142/0x210\n    exit_to_user_mode_loop+0x55/0x100\n    do_syscall_64+0x205/0x2c0\n    entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\nChao further identified [2] a reproducible scenario involving signal\ndelivery: a non-AMX task is preempted by an AMX-enabled task which\nmodifies the XFD MSR.\n\nWhen the non-AMX task resumes and reloads XSTATE with init values,\na warning is triggered due to a mismatch between fpstate::xfd and the\nCPU's current XFD state. fpu__clear_user_states() does not currently\nre-synchronize the XFD state after such preemption.\n\nInvoke xfd_update_state() which detects and corrects the mismatch if\nthere is a dynamic feature.\n\nThis also benefits the sigreturn path, as fpu__restore_sig() may call\nfpu__clear_user_states() when the sigframe is inaccessible.\n\n[ dhansen: minor changelog munging ]\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}