CVE-2023-53996 x86/sev: Make enc_dec_hypercall() accept a size instead of npages
Incorrect page rounding in SEV hypercalls causes data corruption during live migration by marking non-aligned pages as decrypted.
- 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-2023-53996?
CVE-2023-53996 is a critical vulnerability in Linux, published on 24 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:
x86/sev: Make enc_dec_hypercall() accept a size instead of npages
enc_dec_hypercall() accepted a page count instead of a size, which forced its callers to round up. As a result, non-page aligned vaddrs caused pages to be spuriously marked as decrypted via the encryption status hypercall, which in turn caused consistent corruption of pages during live migration. Live migration requires accurate encryption status information to avoid migrating pages from the wrong perspective.
Which versions are affected by CVE-2023-53996?
How do I fix CVE-2023-53996?
Apply the vendor's patch.
Is CVE-2023-53996 being exploited?
There is no known exploitation of CVE-2023-53996 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53996, DEBIAN-CVE-2023-53996, GHSA-5899-4q59-gc9f, UBUNTU-CVE-2023-53996.