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Fencer Vulns
critical 9.3

CVE-2023-53996 in the critical feed json

x86/sev: Make enc_dec_hypercall() accept a size instead of npages

published 2025-12-24 10 mo ago modified 2026-08-05 3 mo ago also EUVD-2025-205158

cvss
9.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 6.1.53, 6.4.16, 6.5.3, 6.6
  • linux Debian 12 6.1.55-1
  • linux Debian 14, Debian 13 6.5.3-1

debian advisories DEBIAN-CVE-2023-53996

  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1115.124
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1044.52
  • linux-gcp-5.15 Ubuntu 20.04 LTS 5.15.0-1044.52~20.04.1
  • linux-gcp-5.4 Ubuntu Pro 18.04 LTS 5.4.0-1115.124~18.04.1
  • linux-gcp-fips Ubuntu Pro FIPS-updates 20.04 LTS 5.4.0-1115.124+fips1

ubuntu advisories UBUNTU-CVE-2023-53996

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 8 4.18.0-553.el8_10
  • perf RHEL 8 4.18.0-553.el8_10
  • bpftool RHEL 8 4.18.0-553.el8_10
  • kernel-core RHEL 8 4.18.0-553.el8_10
  • kernel-tools RHEL 8 4.18.0-553.el8_10
  • python3-perf RHEL 8 4.18.0-553.el8_10
  • kernel-modules RHEL 8 4.18.0-553.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.el8_10

red hat advisories RHSA-2024:3138RHSA-2023:7749RHSA-2024:0575

  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-64kb SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS, SLE High Performance Computing 15 SP4-ESPOS 5.14.21-150400.24.194.1
  • kernel-syms SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.14.21-150400.24.194.1
  • kernel-source SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.14.21-150400.24.194.1
  • kernel-default SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +5 more 5.14.21-150400.24.194.1
  • kernel-obs-build SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.14.21-150400.24.194.1
  • kernel-default-base SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 5.14.21-150400.24.194.1.150400.24.98.3

suse advisories SUSE-SU-2026:20845-1SUSE-SU-2026:20876-1SUSE-SU-2026:0617-1SUSE-SU-2026:20477-1SUSE-SU-2026:20498-1SUSE-SU-2026:0411-1

  • kernel Rocky Linux 8 4.18.0-553.123.1.el8_10.cloud.0.1

rocky linux advisories RXSA-2024:3138

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-53996 updated cvss 5.7

kernel: x86/sev: Make enc_dec_hypercall() accept a size instead of npages

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +6 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available “Fix deferred”
  • Red Hat CodeReady Linux Builder (v. 9) libperf 5.14.0-362.13.1.el9_3, kernel-debuginfo-common-s390x 5.14.0-362.13.1.el9_3, kernel-debuginfo-common-x86_64 5.14.0-362.13.1.el9_3, kernel-debuginfo-common-aarch64 5.14.0-362.13.1.el9_3, kernel-debuginfo-common-ppc64le 5.14.0-362.13.1.el9_3
    fixed: vendor fix RHSA-2023:7749
  • Red Hat CodeReady Linux Builder EUS (v.8.8) kernel-debuginfo-common-x86_64 4.18.0-477.43.1.el8_8, kernel-debuginfo-common-aarch64 4.18.0-477.43.1.el8_8, kernel-debuginfo-common-ppc64le 4.18.0-477.43.1.el8_8
    fixed: vendor fix RHSA-2024:0575
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-362.13.1.el9_3, perf 5.14.0-362.13.1.el9_3, rtla 5.14.0-362.13.1.el9_3, kernel-devel-matched 5.14.0-362.13.1.el9_3, kernel-64k-devel-matched 5.14.0-362.13.1.el9_3, kernel-debug-devel-matched 5.14.0-362.13.1.el9_3, +6 more
    fixed: vendor fix RHSA-2023:7749
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.el8_10, kernel 4.18.0-553.el8_10, bpftool 4.18.0-553.el8_10, kernel-core 4.18.0-553.el8_10, kernel-tools 4.18.0-553.el8_10, python3-perf 4.18.0-553.el8_10, +15 more
    fixed: vendor fix RHSA-2024:3138
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.2.0-362.13.1.el9_3, kernel 5.14.0-362.13.1.el9_3, kernel-64k 5.14.0-362.13.1.el9_3, kernel-core 5.14.0-362.13.1.el9_3, kernel-tools 5.14.0-362.13.1.el9_3, python3-perf 5.14.0-362.13.1.el9_3, +28 more
    fixed: vendor fix RHSA-2023:7749
  • Red Hat Enterprise Linux BaseOS EUS (v.8.8) perf 4.18.0-477.43.1.el8_8, kernel 4.18.0-477.43.1.el8_8, bpftool 4.18.0-477.43.1.el8_8, kernel-core 4.18.0-477.43.1.el8_8, kernel-tools 4.18.0-477.43.1.el8_8, python3-perf 4.18.0-477.43.1.el8_8, +15 more
    fixed: vendor fix RHSA-2024:0575
show 3 more
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.el8_10
    fixed: vendor fix RHSA-2024:3138
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-362.13.1.el9_3, kernel-rt-core 5.14.0-362.13.1.el9_3, kernel-rt-modules 5.14.0-362.13.1.el9_3, kernel-rt-debug-core 5.14.0-362.13.1.el9_3, kernel-rt-modules-core 5.14.0-362.13.1.el9_3, kernel-rt-debug-modules 5.14.0-362.13.1.el9_3, +4 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-362.13.1.el9_3, kernel-rt-kvm 5.14.0-362.13.1.el9_3, kernel-rt-core 5.14.0-362.13.1.el9_3, kernel-rt-modules 5.14.0-362.13.1.el9_3, kernel-rt-debug-kvm 5.14.0-362.13.1.el9_3, kernel-rt-debug-core 5.14.0-362.13.1.el9_3, +6 more
    fixed: vendor fix RHSA-2023:7749
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.11% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.3 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.