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Vulnerability · Published Dec 24, 2025 · Assigned by Linux

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

Critical 9.3

In plain English

A critical-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.3Critical
Exploit odds (30 days)0.1%top 98.7% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.55-1DEBIAN-CVE-2023-53996
Debian:13linux6.5.3-1DEBIAN-CVE-2023-53996
Debian:14linux6.5.3-1DEBIAN-CVE-2023-53996
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-gcp5.15.0-1044.52UBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2023-53996
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2023-53996
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2023-53996

Affected products (as reported)

VendorProductVersions
Linux Linux 064ce6c550a0630789978bfec7a13ab2bd1bdcdf – before ba50e7773a99a109a1ea6f753b766a080d3b21cc064ce6c550a0630789978bfec7a13ab2bd1bdcdf – before 6615212d8e131b45bd9705b0d69cc0d2f624666f064ce6c550a0630789978bfec7a13ab2bd1bdcdf – before 8ae7457e71a320867d868f2622d7c643596e4f43064ce6c550a0630789978bfec7a13ab2bd1bdcdf – before ac3f9c9f1b37edaa7d1a9b908bc79d843955a1a2
Linux Linux 5.16

References