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CVE-2023-4208

24
FAUCET Score

CVE-2023-4208 is a use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component, affecting Debian and Linux kernel versions. This flaw allows a local attacker to achieve privilege escalation by manipulating filter updates, leading to a use-after-free condition. Rated 7.8 HIGH, it has a low attack complexity and no user interaction required, potentially resulting in high impact to confidentiality, integrity, and availability. Currently, there is no evidence of active exploitation, public exploit code, or significant community discussion, and it is not listed in the KEV catalog.

Impacted Technologies

VendorProductVersion(s)CPE
>= 3.18, < 6.5CPE match
cpe:2.3:a:linux:kernel:*:*:*:*:*:*:*:*
>= 3.18, < 4.14.322CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 4.15, < 4.19.291CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 4.20, < 5.4.253CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 5.5, < 5.10.190CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.8HIGH

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.30%
Probability of exploitation in next 30 days
EPSS Percentile
21.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0030 is in the 58th percentile among its peer group of 17,070 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (16)

microsoftpatch availablevia msrc
Product: 18282-16823Fixed in: 5.15.131.1-2
microsoftpatch availablevia msrc
Product: cbl2 kernel 5.15.131.1-2 on CBL Mariner 2.0Fixed in: 5.15.131.1-2
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel-rt-0:3.10.0-1160.105.1.rt56.1256.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel-0:3.10.0-1160.105.1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.6 Advanced Update Support(Disable again in 2026 - SPRHEL-7118)Fixed in: kernel-0:3.10.0-957.109.1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.7 Advanced Update SupportFixed in: kernel-0:3.10.0-1062.82.1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt-0:4.18.0-513.5.1.rt7.307.el8_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-0:4.18.0-513.5.1.el8_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.8 Extended Update SupportFixed in: kernel-0:4.18.0-477.36.1.el8_8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.8 Extended Update SupportFixed in: kpatch-patch
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: kernel-0:5.14.0-362.8.1.el9_3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.2 Extended Update SupportFixed in: kernel-0:5.14.0-284.40.1.el9_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.2 Extended Update SupportFixed in: kernel-rt-0:5.14.0-284.40.1.rt14.325.el9_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.2 Extended Update SupportFixed in: kpatch-patch
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kpatch-patch
View patch
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: kernel-rt

Vendor Advisories (2)

microsoft2023-Sep/CVE-2023-4208Important

Use-after-free in Linux kernel's net/sched: cls_u32 component

Sep 12, 2023
redhatCVE-2023-4208Important

kernel: net/sched: Use-after-free vulnerabilities in the net/sched classifiers: cls_fw, cls_u32 and cls_route

Jul 29, 2023

References

git.kernel.org / pub/scm/linux/kernel/git/torvalds/linux.git/commit
Vendor Advisory
kernel.dance / 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81
Vendor Advisory
lists.debian.org / debian-lts-announce/2024/01/msg00004.html
Third Party Advisory
debian.org / security/2023/dsa-5492
Third Party Advisory