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Fencer Vulns
high 7.5

CVE-2022-50668 json

ext4: fix deadlock due to mbcache entry corruption

published 2025-12-09 11 mo ago modified 2026-08-05 3 mo ago also EUVD-2022-55737

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 57%
public exploits
0
none known

Summary

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

ext4: fix deadlock due to mbcache entry corruption

When manipulating xattr blocks, we can deadlock infinitely looping inside ext4_xattr_block_set() where we constantly keep finding xattr block for reuse in mbcache but we are unable to reuse it because its reference count is too big. This happens because cache entry for the xattr block is marked as reusable (e_reusable set) although its reference count is too big. When this inconsistency happens, this inconsistent state is kept indefinitely and so ext4_xattr_block_set() keeps retrying indefinitely.

The inconsistent state is caused by non-atomic update of e_reusable bit. e_reusable is part of a bitfield and e_reusable update can race with update of e_referenced bit in the same bitfield resulting in loss of one of the updates. Fix the problem by using atomic bitops instead.

This bug has been around for many years, but it became *much* easier to hit after commit 65f8b80053a1 ("ext4: fix race when reusing xattr blocks").

Patch / fix

  • Linux Linux 4.19.270, 5.4.229, 5.10.163, 5.15.87, 6.0.18, 6.1.4, 6.2
  • linux Debian 14, Debian 13, Debian 12 6.1.4-1

debian advisories DEBIAN-CVE-2022-50668

  • linux Ubuntu 20.04 LTS 5.4.0-144.161
  • linux Ubuntu 22.04 LTS 5.15.0-69.76
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1097.105
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1033.37
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1101.110
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1031.38
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1030.35
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1045.50

ubuntu advisories UBUNTU-CVE-2022-50668

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-2023:2458

  • 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
  • kernel-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.142.1
  • kernel-source-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.142.1

suse advisories SUSE-SU-2026:0617-1SUSE-SU-2026:0411-1SUSE-SU-2026:0369-1SUSE-SU-2026:0350-1SUSE-SU-2026:0317-1SUSE-SU-2026:0316-1

  • 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-2022-50668 updated cvss 4.7

kernel: ext4: fix deadlock due to mbcache entry corruption

  • 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 Enterprise Linux AppStream (v. 9) perf 5.14.0-284.11.1.el9_2, rtla 5.14.0-284.11.1.el9_2, kernel-devel-matched 5.14.0-284.11.1.el9_2, kernel-64k-devel-matched 5.14.0-284.11.1.el9_2, kernel-debug-devel-matched 5.14.0-284.11.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.11.1.el9_2, +5 more
    fixed: vendor fix RHSA-2023:2458
  • 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 7.0.0-284.11.1.el9_2, kernel 5.14.0-284.11.1.el9_2, kernel-64k 5.14.0-284.11.1.el9_2, kernel-core 5.14.0-284.11.1.el9_2, kernel-tools 5.14.0-284.11.1.el9_2, python3-perf 5.14.0-284.11.1.el9_2, +28 more
    fixed: vendor fix RHSA-2023:2458
  • 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 CRB (v. 9) kernel-debuginfo-common-s390x 5.14.0-284.11.1.el9_2, kernel-debuginfo-common-x86_64 5.14.0-284.11.1.el9_2, kernel-debuginfo-common-aarch64 5.14.0-284.11.1.el9_2, kernel-debuginfo-common-ppc64le 5.14.0-284.11.1.el9_2
    fixed: vendor fix RHSA-2023:2458
  • 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

0.81% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/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.