CVE-2026-31470 virt: tdx-guest: Fix handling of host controlled 'quote' buffer length
A malicious host can leak kernel memory to guest userspace in Intel TDX environments by manipulating quote buffer lengths, potentially crossing container boundaries.
- 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-2026-31470?
CVE-2026-31470 is a high-severity vulnerability in Linux kernel, published on 22 Apr 2026. 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:
virt: tdx-guest: Fix handling of host controlled 'quote' buffer length
Validate host controlled value `quote_buf->out_len` that determines how many bytes of the quote are copied out to guest userspace. In TDX environments with remote attestation, quotes are not considered private, and can be forwarded to an attestation server.
Catch scenarios where the host specifies a response length larger than the guest's allocation, or otherwise races modifying the response while the guest consumes it.
This prevents contents beyond the pages allocated for `quote_buf` (up to TSM_REPORT_OUTBLOB_MAX) from being read out to guest userspace, and possibly forwarded in attestation requests.
Recall that some deployments want per-container configs-tsm-report interfaces, so the leak may cross container protection boundaries, not just local root.
Which versions are affected by CVE-2026-31470?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31470?
Apply the vendor's patch.
Is CVE-2026-31470 being exploited?
There is no known exploitation of CVE-2026-31470 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31470, DEBIAN-CVE-2026-31470, GHSA-86qf-jwhq-f4jq, ROOT-OS-DEBIAN-13-CVE-2026-31470, ROOT-OS-UBUNTU-2404-CVE-2026-31470, UBUNTU-CVE-2026-31470.