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Fencer Vulns
high 7.8

CVE-2021-28375 json

An issue was discovered in the Linux kernel through 5.11.6.

published 2021-03-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-15058

cvss
7.8
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

An issue was discovered in the Linux kernel through 5.11.6. fastrpc_internal_invoke in drivers/misc/fastrpc.c does not prevent user applications from sending kernel RPC messages, aka CID-20c40794eb85. This is a related issue to CVE-2019-2308.

Patch / fix

  • linux linux_kernel 5.4.106, 5.10.24, 5.11.7
  • linux Debian 14, Debian 13, Debian 12 5.10.24-1

debian advisories DEBIAN-CVE-2021-28375

  • linux Ubuntu 20.04 LTS 5.4.0-73.82
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1048.50
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1043.46
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1043.45
  • linux-kvm Ubuntu 20.04 LTS 5.4.0-1039.40
  • linux-azure Ubuntu 20.04 LTS 5.4.0-1047.49
  • linux-gkeop Ubuntu 20.04 LTS 5.4.0-1015.16
  • linux-raspi Ubuntu 20.04 LTS 5.4.0-1035.38

ubuntu advisories UBUNTU-CVE-2021-28375

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-64kb SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-syms SLE Module for Development Tools 15 SP3 5.3.18-59.5.1
  • kernel-source SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-default SLE Workstation Extension 15 SP3, SLE Module for Legacy 15 SP3, SLE Module for Basesystem 15 SP3 +2 more 5.3.18-59.5.2
  • kernel-preempt SLE Workstation Extension 15 SP3, SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-zfcpdump SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-obs-build SLE Module for Development Tools 15 SP3 5.3.18-59.5.1
  • kernel-default-base SLE Module for Basesystem 15 SP3 5.3.18-59.5.2.18.2.2

suse advisories SUSE-SU-2021:1977-1SUSE-SU-2021:1975-1SUSE-SU-2021:1625-1SUSE-SU-2021:1238-1SUSE-SU-2021:1211-1SUSE-SU-2021:1177-1

  • kernel-64kb openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-syms openSUSE Leap 15.3 5.3.18-59.5.1
  • kernel-obs-qa openSUSE Leap 15.3 5.3.18-59.5.1
  • kernel-source openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-default openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-preempt openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-kvmsmall openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-zfcpdump openSUSE Leap 15.3 5.3.18-59.5.2

opensuse advisories openSUSE-SU-2021:1977-1openSUSE-SU-2021:1975-1openSUSE-SU-2021:0758-1openSUSE-SU-2021:0532-1

  • kernel CBL-Mariner 2.0 5.10.78.1-1

azure linux advisories AZL-6535

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • linux Arch Linux 5.11.7.arch1-1
  • linux-zen Arch Linux 5.11.7.zen1-1
  • linux-hardened Arch Linux 5.11.7.hardened1-1
  • linux-lts Arch Linux 5.10.24-1

arch linux advisories AVG-1685AVG-1686AVG-1687AVG-1688

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-2021-28375 updated cvss 7.4

kernel: fastrpc_internal_invoke in drivers/misc/fastrpc.c does not prevent user applications from sending kernel RPC messages

  • Red Hat Enterprise Linux 5 kernel 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, kernel-alt, python-perf, +9 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 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

0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

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.