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Fencer Vulns
medium 5.5

CVE-2022-48769 json

efi: runtime: avoid EFIv2 runtime services on Apple x86 machines

published 2024-06-20 2 y ago modified 2026-06-17 4 mo ago also EUVD-2022-53648

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

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

efi: runtime: avoid EFIv2 runtime services on Apple x86 machines

Aditya reports [0] that his recent MacbookPro crashes in the firmware when using the variable services at runtime. The culprit appears to be a call to QueryVariableInfo(), which we did not use to call on Apple x86 machines in the past as they only upgraded from EFI v1.10 to EFI v2.40 firmware fairly recently, and QueryVariableInfo() (along with UpdateCapsule() et al) was added in EFI v2.00.

The only runtime service introduced in EFI v2.00 that we actually use in Linux is QueryVariableInfo(), as the capsule based ones are optional, generally not used at runtime (all the LVFS/fwupd firmware update infrastructure uses helper EFI programs that invoke capsule update at boot time, not runtime), and not implemented by Apple machines in the first place. QueryVariableInfo() is used to 'safely' set variables, i.e., only when there is enough space. This prevents machines with buggy firmwares from corrupting their NVRAMs when they run out of space.

Given that Apple machines have been using EFI v1.10 services only for the longest time (the EFI v2.0 spec was released in 2006, and Linux support for the newly introduced runtime services was added in 2011, but the MacbookPro12,1 released in 2015 still claims to be EFI v1.10 only), let's avoid the EFI v2.0 ones on all Apple x86 machines.

[0] https://lore.kernel.org/all/6D757C75-65B1-468B-842D-10410081A8E4@live.com/

Patch / fix

  • Linux Linux 3.3, 3.5, 3.6, 3.7, 5.10.96, 5.15.19, 5.16.5, 5.17
  • linux Debian 14, Debian 13, Debian 12 5.16.7-1

debian advisories DEBIAN-CVE-2022-48769

  • kernel-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.197.1
  • kernel-syms-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.197.1
  • kernel-source-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.197.1
  • kernel-syms SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.228.1
  • kernel-source SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.228.1
  • kernel-default SLES for SAP 12 SP5, SLES 12 SP5, SLE Workstation Extension 12 SP5 +2 more 4.12.14-122.228.1
  • kernel-obs-build SLE Software Development Kit 12 SP5 4.12.14-122.228.2
  • kernel-rt SLE Real Time 12 SP5 4.12.14-10.200.1

suse advisories SUSE-SU-2024:3252-1SUSE-SU-2024:3251-1SUSE-SU-2024:3189-1SUSE-SU-2024:2939-1SUSE-SU-2024:2929-1SUSE-SU-2024:2902-1

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-2022-48769 updated cvss 4.4

kernel: efi: runtime: avoid EFIv2 runtime services on Apple x86 machines

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    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
2 y ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.