high 7.1

CVE-2021-4204 json

An out-of-bounds (OOB) memory access flaw was found in the Linux kernel's eBPF due to an Improper Input Validation.

published 2022-08-24 4 y ago modified 2026-11-02 6 d ago also EUVD-2021-34062

cvss: 7.1; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.2%; EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits: 0; none known

An out-of-bounds (OOB) memory access flaw was found in the Linux kernel's eBPF due to an Improper Input Validation. This flaw allows a local attacker with a special privilege to crash the system or leak internal information.

Patch / fix

fixed in 1 distros 6 links 1

linux linux_kernel 5.8.0

debian ubuntu red hat suse almalinux rocky linux

linux Debian 14, Debian 13, Debian 12 5.17.3-1

debian advisories DEBIAN-CVE-2021-4204

linux-aws-5.11 Ubuntu 20.04 LTS 5.11.0-1025.27~20.04.1
linux-aws-5.13 Ubuntu 20.04 LTS 5.13.0-1011.12~20.04.1
linux-gcp-5.11 Ubuntu 20.04 LTS 5.11.0-1026.29~20.04.1
linux-gcp-5.13 Ubuntu 20.04 LTS 5.13.0-1012.15~20.04.1
linux-hwe-5.11 Ubuntu 20.04 LTS 5.11.0-46.51~20.04.1
linux-hwe-5.13 Ubuntu 20.04 LTS 5.13.0-25.26~20.04.1
linux-oem-5.10 Ubuntu 20.04 LTS 5.10.0-1055.58
linux-oem-5.13 Ubuntu 20.04 LTS 5.13.0-1026.32

ubuntu advisories UBUNTU-CVE-2021-4204

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 RHEL 8 4.18.0-553.rt7.342.el8_10
kernel-rt-kvm RHEL 8 4.18.0-553.rt7.342.el8_10
kernel-rt-core RHEL 8 4.18.0-553.rt7.342.el8_10
kernel-rt-modules RHEL 8 4.18.0-553.rt7.342.el8_10
kernel-rt-debug-kvm RHEL 8 4.18.0-553.rt7.342.el8_10
kernel-rt-debug-core RHEL 8 4.18.0-553.rt7.342.el8_10
kernel-rt-debug-modules RHEL 8 4.18.0-553.rt7.342.el8_10
kernel-rt-modules-extra RHEL 8 4.18.0-553.rt7.342.el8_10

red hat advisories RHSA-2024:10262 RHSA-2024:2950 RHSA-2024:3138 RHSA-2024:0724

dtb-aarch64 openSUSE Leap 15.5 5.14.21-150500.55.80.1
kernel-64kb SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.80.2
kernel-syms SLE Module for Development Tools 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.80.1
kernel-obs-qa openSUSE Leap 15.5 5.14.21-150500.55.80.1
kernel-source SLE Module for Development Tools 15 SP5, SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.80.2
kernel-default SLE Workstation Extension 15 SP5, SLE Module for Legacy 15 SP5, SLE Module for Basesystem 15 SP5 +5 more 5.14.21-150500.55.80.2
kernel-kvmsmall openSUSE Leap 15.5 5.14.21-150500.55.80.2
kernel-zfcpdump SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.80.2

suse advisories SUSE-SU-2024:3483-1 SUSE-SU-2022:2615-1 SUSE-SU-2022:2520-1

kernel-rt AlmaLinux 8 4.18.0-553.rt7.342.el8_10
kernel-rt-kvm AlmaLinux 8 4.18.0-553.rt7.342.el8_10
kernel-rt-core AlmaLinux 8 4.18.0-553.rt7.342.el8_10
kernel-rt-modules AlmaLinux 8 4.18.0-553.rt7.342.el8_10
kernel-rt-debug-kvm AlmaLinux 8 4.18.0-553.rt7.342.el8_10
kernel-rt-debug-core AlmaLinux 8 4.18.0-553.rt7.342.el8_10
kernel-rt-debug-modules AlmaLinux 8 4.18.0-553.rt7.342.el8_10
kernel-rt-modules-extra AlmaLinux 8 4.18.0-553.rt7.342.el8_10

almalinux advisories ALSA-2024:2950 ALSA-2024:3138

kernel Rocky Linux 8 4.18.0-553.123.1.el8_10.cloud.0.1
kernel-rt Rocky Linux 8 4.18.0-553.rt7.342.el8_10
kernel Rocky Linux 8 4.18.0-553.el8_10

rocky linux advisories RXSA-2024:3138 RLSA-2024:2950 RLSA-2024:3138

openwall.com/lists/oss-security/2022/01/11/4 advisory

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-2021-4204 updated 2026-11-07 cvss 7.0

kernel: improper input validation may lead to privilege escalation

Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
affected: workaround, no fix available
Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
affected: workaround, no fix available, no fix planned “Will not fix”
Red Hat CodeReady Linux Builder EUS (v.8.6) kernel-debuginfo-common-x86_64 4.18.0-372.91.1.el8_6, kernel-debuginfo-common-aarch64 4.18.0-372.91.1.el8_6, kernel-debuginfo-common-ppc64le 4.18.0-372.91.1.el8_6
fixed: vendor fix RHSA-2024:0724
Red Hat CodeReady Linux Builder EUS (v.8.8) kernel-debuginfo-common-x86_64 4.18.0-477.81.1.el8_8, kernel-debuginfo-common-aarch64 4.18.0-477.81.1.el8_8, kernel-debuginfo-common-ppc64le 4.18.0-477.81.1.el8_8
fixed: vendor fix RHSA-2024:10262
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 EUS (v.8.6) perf 4.18.0-372.91.1.el8_6, kernel 4.18.0-372.91.1.el8_6, bpftool 4.18.0-372.91.1.el8_6, kernel-core 4.18.0-372.91.1.el8_6, kernel-tools 4.18.0-372.91.1.el8_6, python3-perf 4.18.0-372.91.1.el8_6, +15 more
fixed: vendor fix RHSA-2024:0724
Red Hat Enterprise Linux BaseOS EUS (v.8.8) perf 4.18.0-477.81.1.el8_8, kernel 4.18.0-477.81.1.el8_8, bpftool 4.18.0-477.81.1.el8_8, kernel-core 4.18.0-477.81.1.el8_8, kernel-tools 4.18.0-477.81.1.el8_8, python3-perf 4.18.0-477.81.1.el8_8, +15 more
fixed: vendor fix RHSA-2024:10262
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

show 3 more

Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.rt7.342.el8_10, kernel-rt-kvm 4.18.0-553.rt7.342.el8_10, kernel-rt-core 4.18.0-553.rt7.342.el8_10, kernel-rt-modules 4.18.0-553.rt7.342.el8_10, kernel-rt-debug-kvm 4.18.0-553.rt7.342.el8_10, kernel-rt-debug-core 4.18.0-553.rt7.342.el8_10, +4 more Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.rt7.342.el8_10, kernel-rt-core 4.18.0-553.rt7.342.el8_10, kernel-rt-modules 4.18.0-553.rt7.342.el8_10, kernel-rt-debug-core 4.18.0-553.rt7.342.el8_10, kernel-rt-debug-modules 4.18.0-553.rt7.342.el8_10, kernel-rt-modules-extra 4.18.0-553.rt7.342.el8_10, +2 more
fixed: vendor fix RHSA-2024:2950
Red Hat Virtualization 4 Hypervisor for RHEL 8 perf 4.18.0-372.91.1.el8_6, kernel-debuginfo-common-x86_64 4.18.0-372.91.1.el8_6
fixed: vendor fix RHSA-2024:0724
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: 31 d ago (2026-10-08)

Exploit prediction

1.24% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.1	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected products

n/a kernel

Classification

Weakness

CWE-20 Improper Input Validation
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

Technology feeds

Linux kernel rss critical rss

References

openwall.com /lists/oss-security/2022/01/11/4
mailing-list, patch, third-party-advisory
bugzilla.redhat.com /show_bug.cgi?id=2039178
issue-tracking, third-party-advisory
access.redhat.com /security/cve/CVE-2021-4204
mitigation, third-party-advisory
security-tracker.debian.org /tracker/CVE-2021-4204
third-party-advisory
security.netapp.com /advisory/ntap-20221228-0003/
third-party-advisory

Sources

CVE List CVE-2021-4204
NVD CVE-2021-4204

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.

Summary