CVE-2023-4004 | Kernel: netfilter: use-after-free due to improper element removal in nft_pipapo_remove()

A use-after-free flaw was found in the Linux kernel's netfilter in the way a user triggers the nft_pipapo_remove function with the element, without a NFT_SET_EXT_KEY_END. This issue could allow a local user to crash the system or potentially escalate their privileges on the system.

Published: 2023-07-31 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-4004 is rated Moderate Risk (52/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.96%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-4004

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.02% 0.96% +0.94%
2 2025-11-21 0.06% 0.02% -0.04%
3 2025-11-18 — 0.06% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-4004

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]

Weakness enumeration for CVE-2023-4004

OS Trackers for CVE-2023-4004

vendor priority summary link
debian not yet assigned CVE-2023-4004 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-4004
redhat high — https://access.redhat.com/security/cve/CVE-2023-4004
suse high — https://www.suse.com/security/cve/CVE-2023-4004/
ubuntu high CVE-2023-4004 high priority: Ubuntu including 167 source packages (linux, linux-allwinner, …), 1873 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1428, released 193, not-affected 165, ignored 87. https://ubuntu.com/security/CVE-2023-4004

Affected software / configurations for CVE-2023-4004

Vendor Product Version Raw CPE
linux linux_kernel >= 5.6, < 5.10.188 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.15.123 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.16, < 6.1.42 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.4.7 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
netapp h300s — cpe:2.3:h:netapp:h300s:-:*:*:*:*:*:*:*
netapp h410s — cpe:2.3:h:netapp:h410s:-:*:*:*:*:*:*:*
netapp h500s — cpe:2.3:h:netapp:h500s:-:*:*:*:*:*:*:*
netapp h700s — cpe:2.3:h:netapp:h700s:-:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
debian debian_linux 12.0 cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:*

References for CVE-2023-4004

URL Tags
https://access.redhat.com/errata/RHSA-2023:4961 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:4962 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:4967 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:5069 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:5091 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:5093 Broken Link Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:5221 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:5244 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:5255 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:5548 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:5627 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:7382 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:7389 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:7411 Third Party Advisory VDB Entry
https://access.redhat.com/errata/RHSA-2023:7417 Third Party Advisory VDB Entry
https://access.redhat.com/errata/RHSA-2023:7431 Third Party Advisory VDB Entry
https://access.redhat.com/errata/RHSA-2023:7434 Third Party Advisory VDB Entry
https://access.redhat.com/security/cve/CVE-2023-4004 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2225275 Issue Tracking Third Party Advisory
https://patchwork.ozlabs.org/project/netfilter-devel/patch/[email protected]/ Mailing List Patch Third Party Advisory
http://packetstormsecurity.com/files/175072/Kernel-Live-Patch-Security-Notice-LSN-0098-1.html
http://packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.html
https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html
https://security.netapp.com/advisory/ntap-20231027-0001/
https://www.debian.org/security/2023/dsa-5480
https://www.debian.org/security/2023/dsa-5492
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