FKIE_CVE-2026-31592

Vulnerability from fkie_nvd - Published: 2026-04-24 15:16 - Updated: 2026-04-24 17:51
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Protect *all* of sev_mem_enc_register_region() with kvm->lock Take and hold kvm->lock for before checking sev_guest() in sev_mem_enc_register_region(), as sev_guest() isn't stable unless kvm->lock is held (or KVM can guarantee KVM_SEV_INIT{2} has completed and can't rollack state). If KVM_SEV_INIT{2} fails, KVM can end up trying to add to a not-yet-initialized sev->regions_list, e.g. triggering a #GP Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 110 UID: 0 PID: 72717 Comm: syz.15.11462 Tainted: G U W O 6.16.0-smp-DEV #1 NONE Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 12.52.0-0 10/28/2024 RIP: 0010:sev_mem_enc_register_region+0x3f0/0x4f0 ../include/linux/list.h:83 Code: <41> 80 3c 04 00 74 08 4c 89 ff e8 f1 c7 a2 00 49 39 ed 0f 84 c6 00 RSP: 0018:ffff88838647fbb8 EFLAGS: 00010256 RAX: dffffc0000000000 RBX: 1ffff92015cf1e0b RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000001000 RDI: ffff888367870000 RBP: ffffc900ae78f050 R08: ffffea000d9e0007 R09: 1ffffd4001b3c000 R10: dffffc0000000000 R11: fffff94001b3c001 R12: 0000000000000000 R13: ffff8982ab0bde00 R14: ffffc900ae78f058 R15: 0000000000000000 FS: 00007f34e9dc66c0(0000) GS:ffff89ee64d33000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe180adef98 CR3: 000000047210e000 CR4: 0000000000350ef0 Call Trace: <TASK> kvm_arch_vm_ioctl+0xa72/0x1240 ../arch/x86/kvm/x86.c:7371 kvm_vm_ioctl+0x649/0x990 ../virt/kvm/kvm_main.c:5363 __se_sys_ioctl+0x101/0x170 ../fs/ioctl.c:51 do_syscall_x64 ../arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x6f/0x1f0 ../arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f34e9f7e9a9 Code: <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f34e9dc6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f34ea1a6080 RCX: 00007f34e9f7e9a9 RDX: 0000200000000280 RSI: 000000008010aebb RDI: 0000000000000007 RBP: 00007f34ea000d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f34ea1a6080 R15: 00007ffce77197a8 </TASK> with a syzlang reproducer that looks like: syz_kvm_add_vcpu$x86(0x0, &(0x7f0000000040)={0x0, &(0x7f0000000180)=ANY=[], 0x70}) (async) syz_kvm_add_vcpu$x86(0x0, &(0x7f0000000080)={0x0, &(0x7f0000000180)=ANY=[@ANYBLOB="..."], 0x4f}) (async) r0 = openat$kvm(0xffffffffffffff9c, &(0x7f0000000200), 0x0, 0x0) r1 = ioctl$KVM_CREATE_VM(r0, 0xae01, 0x0) r2 = openat$kvm(0xffffffffffffff9c, &(0x7f0000000240), 0x0, 0x0) r3 = ioctl$KVM_CREATE_VM(r2, 0xae01, 0x0) ioctl$KVM_SET_CLOCK(r3, 0xc008aeba, &(0x7f0000000040)={0x1, 0x8, 0x0, 0x5625e9b0}) (async) ioctl$KVM_SET_PIT2(r3, 0x8010aebb, &(0x7f0000000280)={[...], 0x5}) (async) ioctl$KVM_SET_PIT2(r1, 0x4070aea0, 0x0) (async) r4 = ioctl$KVM_CREATE_VM(0xffffffffffffffff, 0xae01, 0x0) openat$kvm(0xffffffffffffff9c, 0x0, 0x0, 0x0) (async) ioctl$KVM_SET_USER_MEMORY_REGION(r4, 0x4020ae46, &(0x7f0000000400)={0x0, 0x0, 0x0, 0x2000, &(0x7f0000001000/0x2000)=nil}) (async) r5 = ioctl$KVM_CREATE_VCPU(r4, 0xae41, 0x2) close(r0) (async) openat$kvm(0xffffffffffffff9c, &(0x7f0000000000), 0x8000, 0x0) (async) ioctl$KVM_SET_GUEST_DEBUG(r5, 0x4048ae9b, &(0x7f0000000300)={0x4376ea830d46549b, 0x0, [0x46, 0x0, 0x0, 0x0, 0x0, 0x1000]}) (async) ioctl$KVM_RUN(r5, 0xae80, 0x0) Opportunistically use guard() to avoid having to define a new error label and goto usage.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0ff93ff0ba82e9511770e175fa50682a1ab14fb6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/35a0963d361f98bba798fd15d229dcb166c04684
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ab725ac3022469ecd4d7aa7d5646712e98b249d8
Impacted products
Vendor Product Version
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Protect *all* of sev_mem_enc_register_region() with kvm-\u003elock\n\nTake and hold kvm-\u003elock for before checking sev_guest() in\nsev_mem_enc_register_region(), as sev_guest() isn\u0027t stable unless kvm-\u003elock\nis held (or KVM can guarantee KVM_SEV_INIT{2} has completed and can\u0027t\nrollack state).  If KVM_SEV_INIT{2} fails, KVM can end up trying to add to\na not-yet-initialized sev-\u003eregions_list, e.g. triggering a #GP\n\n  Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI\n  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]\n  CPU: 110 UID: 0 PID: 72717 Comm: syz.15.11462 Tainted: G     U  W  O        6.16.0-smp-DEV #1 NONE\n  Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE\n  Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 12.52.0-0 10/28/2024\n  RIP: 0010:sev_mem_enc_register_region+0x3f0/0x4f0 ../include/linux/list.h:83\n  Code: \u003c41\u003e 80 3c 04 00 74 08 4c 89 ff e8 f1 c7 a2 00 49 39 ed 0f 84 c6 00\n  RSP: 0018:ffff88838647fbb8 EFLAGS: 00010256\n  RAX: dffffc0000000000 RBX: 1ffff92015cf1e0b RCX: dffffc0000000000\n  RDX: 0000000000000000 RSI: 0000000000001000 RDI: ffff888367870000\n  RBP: ffffc900ae78f050 R08: ffffea000d9e0007 R09: 1ffffd4001b3c000\n  R10: dffffc0000000000 R11: fffff94001b3c001 R12: 0000000000000000\n  R13: ffff8982ab0bde00 R14: ffffc900ae78f058 R15: 0000000000000000\n  FS:  00007f34e9dc66c0(0000) GS:ffff89ee64d33000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007fe180adef98 CR3: 000000047210e000 CR4: 0000000000350ef0\n  Call Trace:\n   \u003cTASK\u003e\n   kvm_arch_vm_ioctl+0xa72/0x1240 ../arch/x86/kvm/x86.c:7371\n   kvm_vm_ioctl+0x649/0x990 ../virt/kvm/kvm_main.c:5363\n   __se_sys_ioctl+0x101/0x170 ../fs/ioctl.c:51\n   do_syscall_x64 ../arch/x86/entry/syscall_64.c:63 [inline]\n   do_syscall_64+0x6f/0x1f0 ../arch/x86/entry/syscall_64.c:94\n   entry_SYSCALL_64_after_hwframe+0x76/0x7e\n  RIP: 0033:0x7f34e9f7e9a9\n  Code: \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48\n  RSP: 002b:00007f34e9dc6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\n  RAX: ffffffffffffffda RBX: 00007f34ea1a6080 RCX: 00007f34e9f7e9a9\n  RDX: 0000200000000280 RSI: 000000008010aebb RDI: 0000000000000007\n  RBP: 00007f34ea000d69 R08: 0000000000000000 R09: 0000000000000000\n  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\n  R13: 0000000000000000 R14: 00007f34ea1a6080 R15: 00007ffce77197a8\n   \u003c/TASK\u003e\n\nwith a syzlang reproducer that looks like:\n\n  syz_kvm_add_vcpu$x86(0x0, \u0026(0x7f0000000040)={0x0, \u0026(0x7f0000000180)=ANY=[], 0x70}) (async)\n  syz_kvm_add_vcpu$x86(0x0, \u0026(0x7f0000000080)={0x0, \u0026(0x7f0000000180)=ANY=[@ANYBLOB=\"...\"], 0x4f}) (async)\n  r0 = openat$kvm(0xffffffffffffff9c, \u0026(0x7f0000000200), 0x0, 0x0)\n  r1 = ioctl$KVM_CREATE_VM(r0, 0xae01, 0x0)\n  r2 = openat$kvm(0xffffffffffffff9c, \u0026(0x7f0000000240), 0x0, 0x0)\n  r3 = ioctl$KVM_CREATE_VM(r2, 0xae01, 0x0)\n  ioctl$KVM_SET_CLOCK(r3, 0xc008aeba, \u0026(0x7f0000000040)={0x1, 0x8, 0x0, 0x5625e9b0}) (async)\n  ioctl$KVM_SET_PIT2(r3, 0x8010aebb, \u0026(0x7f0000000280)={[...], 0x5}) (async)\n  ioctl$KVM_SET_PIT2(r1, 0x4070aea0, 0x0) (async)\n  r4 = ioctl$KVM_CREATE_VM(0xffffffffffffffff, 0xae01, 0x0)\n  openat$kvm(0xffffffffffffff9c, 0x0, 0x0, 0x0) (async)\n  ioctl$KVM_SET_USER_MEMORY_REGION(r4, 0x4020ae46, \u0026(0x7f0000000400)={0x0, 0x0, 0x0, 0x2000, \u0026(0x7f0000001000/0x2000)=nil}) (async)\n  r5 = ioctl$KVM_CREATE_VCPU(r4, 0xae41, 0x2)\n  close(r0) (async)\n  openat$kvm(0xffffffffffffff9c, \u0026(0x7f0000000000), 0x8000, 0x0) (async)\n  ioctl$KVM_SET_GUEST_DEBUG(r5, 0x4048ae9b, \u0026(0x7f0000000300)={0x4376ea830d46549b, 0x0, [0x46, 0x0, 0x0, 0x0, 0x0, 0x1000]}) (async)\n  ioctl$KVM_RUN(r5, 0xae80, 0x0)\n\nOpportunistically use guard() to avoid having to define a new error label\nand goto usage."
    }
  ],
  "id": "CVE-2026-31592",
  "lastModified": "2026-04-24T17:51:40.810",
  "metrics": {},
  "published": "2026-04-24T15:16:36.667",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0ff93ff0ba82e9511770e175fa50682a1ab14fb6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/35a0963d361f98bba798fd15d229dcb166c04684"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ab725ac3022469ecd4d7aa7d5646712e98b249d8"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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