CVE-2022-49886 x86/tdx: Panic on bad configs that #VE on "private" memory access
A misconfiguration in Intel TDX virtualization can cause the Linux kernel to panic when handling virtualization exceptions on private memory.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-49886?
CVE-2022-49886 is a high-severity denial of service vulnerability in Linux kernel, published on 1 May 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:
x86/tdx: Panic on bad configs that #VE on "private" memory access
All normal kernel memory is "TDX private memory". This includes everything from kernel stacks to kernel text. Handling exceptions on arbitrary accesses to kernel memory is essentially impossible because they can happen in horribly nasty places like kernel entry/exit. But, TDX hardware can theoretically _deliver_ a virtualization exception (#VE) on any access to private memory.
But, it's not as bad as it sounds. TDX can be configured to never deliver these exceptions on private memory with a "TD attribute" called ATTR_SEPT_VE_DISABLE. The guest has no way to *set* this attribute, but it can check it.
Ensure ATTR_SEPT_VE_DISABLE is set in early boot. panic() if it is unset. There is no sane way for Linux to run with this attribute clear so a panic() is appropriate.
There's small window during boot before the check where kernel has an early #VE handler. But the handler is only for port I/O and will also panic() as soon as it sees any other #VE, such as a one generated by a private memory access.
[ dhansen: Rewrite changelog and rebase on new tdx_parse_tdinfo(). Add Kirill's tested-by because I made changes since he wrote this. ]
Which versions are affected by CVE-2022-49886?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49886?
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-2022-49886 being exploited?
There is no known exploitation of CVE-2022-49886 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49886, GHSA-8ww3-pfqc-q6wm, UBUNTU-CVE-2022-49886.