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Fencer Vulns
medium 5.5

CVE-2024-50102 json

x86: fix user address masking non-canonical speculation issue

published 2024-11-05 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-44577

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

x86: fix user address masking non-canonical speculation issue

It turns out that AMD has a "Meltdown Lite(tm)" issue with non-canonical accesses in kernel space. And so using just the high bit to decide whether an access is in user space or kernel space ends up with the good old "leak speculative data" if you have the right gadget using the result:

CVE-2020-12965 “Transient Execution of Non-Canonical Accesses“

Now, the kernel surrounds the access with a STAC/CLAC pair, and those instructions end up serializing execution on older Zen architectures, which closes the speculation window.

But that was true only up until Zen 5, which renames the AC bit [1]. That improves performance of STAC/CLAC a lot, but also means that the speculation window is now open.

Note that this affects not just the new address masking, but also the regular valid_user_address() check used by access_ok(), and the asm version of the sign bit check in the get_user() helpers.

It does not affect put_user() or clear_user() variants, since there's no speculative result to be used in a gadget for those operations.

Patch / fix

  • Linux Linux 6.11.6, 6.12
  • linux Debian 14, Debian 13 6.11.6-1

debian advisories DEBIAN-CVE-2024-50102

  • linux-gcp-6.11 Ubuntu 24.04 LTS 6.11.0-1011.11~24.04.1
  • linux-oem-6.11 Ubuntu 24.04 LTS 6.11.0-1015.15
  • linux-azure-6.11 Ubuntu 24.04 LTS 6.11.0-1012.12~24.04.1
  • linux-nvidia-6.11 Ubuntu 24.04 LTS 6.11.0-1007.7

ubuntu advisories UBUNTU-CVE-2024-50102

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 9 5.14.0-570.12.1.el9_6
  • rv RHEL 9 5.14.0-570.12.1.el9_6
  • perf RHEL 9 5.14.0-570.12.1.el9_6
  • rtla RHEL 9 5.14.0-570.12.1.el9_6
  • libperf RHEL 9 5.14.0-570.12.1.el9_6
  • kernel-rt RHEL 9 5.14.0-570.12.1.el9_6
  • kernel-64k RHEL 9 5.14.0-570.12.1.el9_6
  • kernel-core RHEL 9 5.14.0-570.12.1.el9_6

red hat advisories RHSA-2025:15668RHSA-2025:6966

  • kernel-source Linux Micro 6.1, Linux Micro 6.0 6.4.0-24.1
  • kernel-default Linux Micro 6.1, Linux Micro 6.0 6.4.0-24.1
  • kernel-kvmsmall Linux Micro 6.1, Linux Micro 6.0 6.4.0-24.1
  • kernel-default-base Linux Micro 6.1, Linux Micro 6.0 6.4.0-24.1.21.4
  • kernel-livepatch-MICRO-6-0_Update_4 Linux Micro 6.1, Linux Micro 6.0 1-1.2
  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-22.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-22.1
  • kernel-livepatch-MICRO-6-0-RT_Update_4 Linux Micro 6.1, Linux Micro 6.0 1-1.1

suse advisories SUSE-SU-2025:20164-1SUSE-SU-2025:20247-1SUSE-SU-2025:20163-1SUSE-SU-2025:20246-1SUSE-SU-2024:4387-1SUSE-SU-2024:4318-1

  • kernel-source-longterm openSUSE Tumbleweed 6.12.11-1.1
  • kernel-source openSUSE Tumbleweed 6.11.8-1.1

opensuse advisories openSUSE-SU-2025:14705-1openSUSE-SU-2024:14500-1

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-2024-50102 updated cvss 5.5

kernel: x86: fix user address masking non-canonical speculation issue

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat CodeReady Linux Builder EUS (v.9.4) libperf 5.14.0-427.88.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.88.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.88.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.88.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.88.1.el9_4
    fixed: vendor fix RHSA-2025:15668
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-570.12.1.el9_6, perf 5.14.0-570.12.1.el9_6, rtla 5.14.0-570.12.1.el9_6, python3-perf 5.14.0-570.12.1.el9_6, kernel-devel-matched 5.14.0-570.12.1.el9_6, kernel-64k-devel-matched 5.14.0-570.12.1.el9_6, +7 more
    fixed: vendor fix RHSA-2025:6966
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) rv 5.14.0-427.88.1.el9_4, perf 5.14.0-427.88.1.el9_4, rtla 5.14.0-427.88.1.el9_4, kernel-devel-matched 5.14.0-427.88.1.el9_4, kernel-64k-devel-matched 5.14.0-427.88.1.el9_4, kernel-debug-devel-matched 5.14.0-427.88.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:15668
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-570.12.1.el9_6, kernel-64k 5.14.0-570.12.1.el9_6, kernel-core 5.14.0-570.12.1.el9_6, kernel-tools 5.14.0-570.12.1.el9_6, kernel-modules 5.14.0-570.12.1.el9_6, kernel-64k-core 5.14.0-570.12.1.el9_6, +27 more
    fixed: vendor fix RHSA-2025:6966
  • Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool 7.3.0-427.88.1.el9_4, kernel 5.14.0-427.88.1.el9_4, kernel-64k 5.14.0-427.88.1.el9_4, kernel-core 5.14.0-427.88.1.el9_4, kernel-tools 5.14.0-427.88.1.el9_4, python3-perf 5.14.0-427.88.1.el9_4, +28 more
    fixed: vendor fix RHSA-2025:15668
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-570.12.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.12.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.12.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.12.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.12.1.el9_6 Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-570.12.1.el9_6, kernel-rt-64k 5.14.0-570.12.1.el9_6, kernel-rt-core 5.14.0-570.12.1.el9_6, kernel-rt-modules 5.14.0-570.12.1.el9_6, kernel-rt-64k-core 5.14.0-570.12.1.el9_6, kernel-rt-debug-core 5.14.0-570.12.1.el9_6, +14 more
    fixed: vendor fix RHSA-2025:6966
  • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt 5.14.0-427.88.1.el9_4, kernel-rt-core 5.14.0-427.88.1.el9_4, kernel-rt-modules 5.14.0-427.88.1.el9_4, kernel-rt-debug-core 5.14.0-427.88.1.el9_4, kernel-rt-modules-core 5.14.0-427.88.1.el9_4, kernel-rt-debug-modules 5.14.0-427.88.1.el9_4, +4 more
    fixed: vendor fix RHSA-2025:15668
show 3 more
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-570.12.1.el9_6, kernel-rt-kvm 5.14.0-570.12.1.el9_6, kernel-rt-core 5.14.0-570.12.1.el9_6, kernel-rt-modules 5.14.0-570.12.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.12.1.el9_6, kernel-rt-debug-core 5.14.0-570.12.1.el9_6, +6 more
    fixed: vendor fix RHSA-2025:6966
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt 5.14.0-427.88.1.el9_4, kernel-rt-kvm 5.14.0-427.88.1.el9_4, kernel-rt-core 5.14.0-427.88.1.el9_4, kernel-rt-modules 5.14.0-427.88.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.88.1.el9_4, kernel-rt-debug-core 5.14.0-427.88.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:15668
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux AppStream EUS (v.9.4) kernel-doc 5.14.0-427.88.1.el9_4
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
13 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected products

  • Linux Linux

Classification

Weakness
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.