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Fencer Vulns
medium 5.5

CVE-2021-4148 json

A vulnerability was found in the Linux kernel's block_invalidatepage in fs/buffer.c in the filesystem.

published 2022-03-23 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-34016

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

A vulnerability was found in the Linux kernel's block_invalidatepage in fs/buffer.c in the filesystem. A missing sanity check may allow a local attacker with user privilege to cause a denial of service (DOS) problem.

Patch / fix

  • linux linux_kernel 5.14.16
  • linux Debian 14, Debian 13, Debian 12 5.14.16-1

debian advisories DEBIAN-CVE-2021-4148

  • linux-aws-5.13 Ubuntu 20.04 LTS 5.13.0-1012.13~20.04.1
  • linux-gcp-5.13 Ubuntu 20.04 LTS 5.13.0-1013.16~20.04.1
  • linux-hwe-5.13 Ubuntu 20.04 LTS 5.13.0-28.31~20.04.1
  • linux-oem-5.14 Ubuntu 20.04 LTS 5.14.0-1008.8
  • linux-azure-5.13 Ubuntu 20.04 LTS 5.13.0-1013.15~20.04.1
  • linux-oracle-5.13 Ubuntu 20.04 LTS 5.13.0-1016.20~20.04.1

ubuntu advisories UBUNTU-CVE-2021-4148

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-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.106.1
  • kernel-source-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.106.1
  • dtb-aarch64 openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-64kb SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-syms SLE Module for Development Tools 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-obs-qa openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-source SLE Module for Development Tools 15 SP5, SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-default SLE Workstation Extension 15 SP5, SLE Module for Legacy 15 SP5, SLE Module for Basesystem 15 SP5 +4 more 5.14.21-150500.55.68.1

suse advisories SUSE-SU-2025:0231-1SUSE-SU-2024:2190-1SUSE-SU-2024:2189-1SUSE-SU-2024:2019-1SUSE-SU-2024:2008-1

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-2021-4148 updated cvss 5.1

kernel: Improper implementation of block_invalidatepage() allows users to crash the kernel

  • 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 Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more 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, +82 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

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • lkml.org https://lkml.org/lkml/2021/9/12/323 referenced PoC, tagged "exploit" by a source, unverified
  • lkml.org https://lkml.org/lkml/2021/9/17/1037 referenced PoC, tagged "exploit" by a source, unverified

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
NVD 2.0 4.9 AV:L/AC:L/Au:N/C:N/I:N/A:C

Affected products

  • n/a kernel

Classification

Weakness
  • CWE-354 Improper Validation of Integrity Check Value
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.