What’s Vulnerable › Vulnerabilities

CVE-2023-53996: x86/sev: Make enc_dec_hypercall() accept a size instead of npages

• Severity: critical (CVSS 9.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-24 · updated 2026-08-04

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.

Affected products

• Linux kernel: 5.16 — fixed in 6.6

How to fix

Upgrade to a fixed version: Linux kernel 6.6. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/6615212d8e131b45bd9705b0d69cc0d2f624666f
• https://git.kernel.org/stable/c/8ae7457e71a320867d868f2622d7c643596e4f43
• https://git.kernel.org/stable/c/ac3f9c9f1b37edaa7d1a9b908bc79d843955a1a2
• https://git.kernel.org/stable/c/ba50e7773a99a109a1ea6f753b766a080d3b21cc

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