CVE-2022-50851 vhost_vdpa: fix the crash in unmap a large memory
A local attacker with low privileges can crash the Linux kernel by unmapping large memory in vhost_vdpa, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-50851?
CVE-2022-50851 is a denial of service vulnerability in Linux, published on 30 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
vhost_vdpa: fix the crash in unmap a large memory
While testing in vIOMMU, sometimes Guest will unmap very large memory, which will cause the crash. To fix this, add a new function vhost_vdpa_general_unmap(). This function will only unmap the memory that saved in iotlb.
Call Trace: [ 647.820144] ------------[ cut here ]------------ [ 647.820848] kernel BUG at drivers/iommu/intel/iommu.c:1174! [ 647.821486] invalid opcode: 0000 [#1] PREEMPT SMP PTI [ 647.822082] CPU: 10 PID: 1181 Comm: qemu-system-x86 Not tainted 6.0.0-rc1home_lulu_2452_lulu7_vhost+ #62 [ 647.823139] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.15.0-29-g6a62e0cb0dfe-prebuilt.qem4 [ 647.824365] RIP: 0010:domain_unmap+0x48/0x110 [ 647.825424] Code: 48 89 fb 8d 4c f6 1e 39 c1 0f 4f c8 83 e9 0c 83 f9 3f 7f 18 48 89 e8 48 d3 e8 48 85 c0 75 59 [ 647.828064] RSP: 0018:ffffae5340c0bbf0 EFLAGS: 00010202 [ 647.828973] RAX: 0000000000000001 RBX: ffff921793d10540 RCX: 000000000000001b [ 647.830083] RDX: 00000000080000ff RSI: 0000000000000001 RDI: ffff921793d10540 [ 647.831214] RBP: 0000000007fc0100 R08: ffffae5340c0bcd0 R09: 0000000000000003 [ 647.832388] R10: 0000007fc0100000 R11: 0000000000100000 R12: 00000000080000ff [ 647.833668] R13: ffffae5340c0bcd0 R14: ffff921793d10590 R15: 0000008000100000 [ 647.834782] FS: 00007f772ec90640(0000) GS:ffff921ce7a80000(0000) knlGS:0000000000000000 [ 647.836004] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 647.836990] CR2: 00007f02c27a3a20 CR3: 0000000101b0c006 CR4: 0000000000372ee0 [ 647.838107] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 647.839283] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 647.840666] Call Trace: [ 647.841437] <TASK> [ 647.842107] intel_iommu_unmap_pages+0x93/0x140 [ 647.843112] __iommu_unmap+0x91/0x1b0 [ 647.844003] iommu_unmap+0x6a/0x95 [ 647.844885] vhost_vdpa_unmap+0x1de/0x1f0 [vhost_vdpa] [ 647.845985] vhost_vdpa_process_iotlb_msg+0xf0/0x90b [vhost_vdpa] [ 647.847235] ? _raw_spin_unlock+0x15/0x30 [ 647.848181] ? _copy_from_iter+0x8c/0x580 [ 647.849137] vhost_chr_write_iter+0xb3/0x430 [vhost] [ 647.850126] vfs_write+0x1e4/0x3a0 [ 647.850897] ksys_write+0x53/0xd0 [ 647.851688] do_syscall_64+0x3a/0x90 [ 647.852508] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 647.853457] RIP: 0033:0x7f7734ef9f4f [ 647.854408] Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 29 76 f8 ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c8 [ 647.857217] RSP: 002b:00007f772ec8f040 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 [ 647.858486] RAX: ffffffffffffffda RBX: 00000000fef00000 RCX: 00007f7734ef9f4f [ 647.859713] RDX: 0000000000000048 RSI: 00007f772ec8f090 RDI: 0000000000000010 [ 647.860942] RBP: 00007f772ec8f1a0 R08: 0000000000000000 R09: 0000000000000000 [ 647.862206] R10: 0000000000000001 R11: 0000000000000293 R12: 0000000000000010 [ 647.863446] R13: 0000000000000002 R14: 0000000000000000 R15: ffffffff01100000 [ 647.864692] </TASK> [ 647.865458] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs v] [ 647.874688] ---[ end trace 0000000000000000 ]---
Which versions are affected by CVE-2022-50851?
How do I fix CVE-2022-50851?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2022-50851 being exploited?
There is no known exploitation of CVE-2022-50851 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2022-50851, GHSA-59wc-rrrg-chg9, ROOT-OS-DEBIAN-11-CVE-2022-50851, ROOT-OS-UBUNTU-2204-CVE-2022-50851, UBUNTU-CVE-2022-50851.