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CVE-2021-4159

18
FAUCET Score

CVE-2021-4159 is a Linux kernel vulnerability affecting the EBPF verifier, allowing local attackers with eBPF code insertion permissions to leak internal kernel memory details. This medium-severity flaw (CVSS 4.4) has a local attack vector with low complexity, potentially bypassing kernel exploit mitigations. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
< 5.7CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
10.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.4MEDIUM

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
0.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.24%
Probability of exploitation in next 30 days
EPSS Percentile
14.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0024 is in the 60th percentile among its peer group of 3,720 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (5)

redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise MRG 2Fixed in: kernel
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel-rt

Vendor Advisories (1)

redhatCVE-2021-4159Moderate

kernel: another kernel ptr leak vulnerability via BPF in coerce_reg_to_size

Jan 28, 2022

References

access.redhat.com / security/cve/CVE-2021-4159
Third Party Advisory
bugzilla.redhat.com / show_bug.cgi
Issue Tracking
git.kernel.org / pub/scm/linux/kernel/git/torvalds/linux.git/commit
Mailing ListPatchVendor Advisory
lists.debian.org / debian-lts-announce/2022/10/msg00000.html
Mailing ListThird Party Advisory
security-tracker.debian.org / tracker/CVE-2021-4159
Third Party Advisory