vciy

CVE-2023-4004

INDEX BUILT · 2026-09-20

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

CVE-2023-40044 of 4 sources documented this
28

rank 28 = 0 + 20 + 0 + 8 + 0

rank@v1 · scheduled

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.00941  ·  without this subject the record ranks 28

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 7.8, from NVD  ·  without this subject the record ranks 8

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

no persisting rise in 365 days  ·  without this subject the record ranks 28

How much of the world it touches

NVD CPE configurations

10 products in the CPE ranges  ·  without this subject the record ranks 20

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 28

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$47,000over the next 30 days, if this record is yours
Movementno material movementthe record holds only daily drift and scoring model releases
Basisassumeda published average, not your estate

$47,000 = $4.99M incident cost x 1 exposure x 0.00941 likelihood

udv@v1 · unaudited · wrong for you until you say what you run

$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.

Hindsight · the state

0.00941EPSSNOT IN KEVas of 2026-09-20
Severity7.8 HIGHreceipt
Harmtotal lossreceipt
Exploitationnone in held sources
Defenseunaffected versions publishedreceipt
Movementdoubled within 72hreceipt
PLATEAU10Minimal movement since 2023-08-01, 1095 days at 0.01, as of 2026-07-31. arc-rules@v1

Foresight · where to check next

Microsoft WindowsLinux KernelMicrosoft WindowsMicrosoft Windows4004

This record is one instance of CWE-416, use after free. The index holds 8701 prior instances of this class, 106 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1

Full pattern panel

Prior records in this weakness class. Each is its own record, dated and receipted.
Color is a claim, not decoration:the hostile worldthe defenseno signalspoke length is how much of the record matches, not how bad it is

Running Red Hat Enterprise Linux 8? Check your version

A deterministic range check against the ranges this record publishes. It tells you where a version sits in the record, not whether your deployment is exploitable. No account needed.

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Harm, if it fires from the vector and the weakness

Written for the ticket you're about to file.

Reachneeds local access · low privileges required · no user interaction · low attack complexityreceipt
ImpactComplete confidentiality, integrity and availability lossreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classCWE-416 Use After Freereceipt
Published consequencesCWE-416: Integrity: Modify Memory; Availability: DoS: Crash, Exit, or Restart; Confidentiality: Read Memory; Integrity, Confidentiality, Availability: Execute Unauthorized Code or Commands[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

First unaffected version, by branchkernel 5.10.188; kernel 5.15.123; kernel 6.1.42; kernel 6.4.7receipt
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.

Exploit Status & Known PoCs a ladder, not a score

Current rung: Nothing observed in held sources.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published
  • RUNG 3Exploited in the wild · CISA KEV listed
  • RUNG 4Ransomware campaign use known

Authority who says so

CVSS, the CNA7.8 HIGHreceipt
CVSS, NVD7.8 HIGHreceipt
Exploit probability0.00941 · top 41% of all CVEsreceipt
Blast breadth4 products across 4 vendorsderived
Assigned byredhatreceipt
Recorded changes29 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productRed Hat Enterprise Linux 8; Red Hat Enterprise Linux 8.2 Advanced Update Support; Red Hat Enterprise Linux 8.2 Telecommunications Update Service…receipt
Published rangeslinux kernel >= 5.6 < 5.10.188; linux kernel >= 5.11 < 5.15.123; linux kernel >= 5.16 < 6.1.42; linux kernel >= 6.2 < 6.4.7receipt
Show all 10 published ranges
linux kernel >= 5.6 < 5.10.188
linux kernel >= 5.11 < 5.15.123
linux kernel >= 5.16 < 6.1.42
linux kernel >= 6.2 < 6.4.7
redhat enterprise linux 8.0
redhat enterprise linux 9.0
debian linux 10.0
debian linux 11.0
debian linux 12.0
fedoraproject fedora 38

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

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Attack path

Local accessrequires low privilegesRed Hat Enterprise Linux 8CWE-416 use after freeFull compromise (C/I/A)C:H / I:H / A:Hexploits CWE-416data compromise

What it is stated by the CNA

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. receipt

NVD's analysis a second authority

severity
7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
weakness
CWE-416
affected versions
linux kernel >= 5.6 < 5.10.188; linux kernel >= 5.11 < 5.15.123; linux kernel >= 5.16 < 6.1.42; and 7 more, listed in full below
also scored by
[email protected] 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

check it yourself access.redhat.com access.redhat.com access.redhat.com access.redhat.com access.redhat.com access.redhat.com +14 morereceipt

Movement the material steps

1 Aug 20230.00050
17 Mar 20250.00069 · scoring model v2025.03.14
15 Jun 20260.00958 · scoring model v2026.06.15
31 Jul 20260.00941

This score more than doubled inside 72 hours. Both observations are in the full history below.

Show all 29 observations
1 Aug 20230.00050
5 Aug 20230.00042
20 Sep 20230.00044
30 Dec 20230.00143
14 Sep 20240.00048
17 Dec 20240.00195
17 Mar 20250.00069
29 Mar 20250.00321
30 Mar 20250.00069
15 Apr 20250.00014
13 May 20250.00015
16 Jul 20250.00016
31 Jul 20250.00015
15 Aug 20250.00014
1 Sep 20250.00015
16 Sep 20250.00019
18 Nov 20250.00059
21 Nov 20250.00019
4 Dec 20250.00015
18 Feb 20260.00016
25 Feb 20260.00015
27 May 20260.00016
28 May 20260.00017
12 Jun 20260.00016
15 Jun 20260.00958
3 Jul 20260.0095
14 Jul 20260.00958
20 Jul 20260.00933
31 Jul 20260.00941

29 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt

The full biography

EPSS 0.00941Published2023-07-31Index as of2026-07-31

Exploit probability more than doubled between 2026-06-12 and 2026-06-15 (0.00016 → 0.00958) and the record had been public for 3 years when this index was last written.

Published 2023-07-31 receipt · Index as of 2026-07-31 derived

The pattern, elsewhere

This record is one instance of CWE-416, use after free. The index holds 8701 prior instances of this class, 106 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]

CVE-2025-29824 · Microsoft Windows 10 Version 1507matches 8 of 9KEV listed · 2025receipt
CVE-2024-1086 · Linux Kernelmatches 8 of 9KEV listed · 2024receipt
CVE-2021-40449 · Microsoft Windows 10 Version 1809matches 8 of 9KEV listed · 2021receipt
CVE-2025-21334 · Microsoft Windows 10 Version 21H2matches 8 of 9KEV listed · 2025receipt
CVE-2025-21335 · Microsoft Windows 10 Version 21H2matches 8 of 9KEV listed · 2025receipt
CVE-2025-30400 · Microsoft Windows 10 Version 1809matches 8 of 9KEV listed · 2025receipt

"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1

8701 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.

No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.

Siblings and hubs

Records related to this one

Its defect family

red hat enterprise linux 8

Of the 11 records in this family, this is the only one whose title names netfilter improper element.

Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.

Family membership: held values

This record is one of a group, and the group's page describes all of them. This page is kept and dated, and the defect family's own page is the one we offer for indexing: the whole group.

Browse the index from here

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What usually comes next

Everything above needs no account. What is below is work: assembling it, scoping it to your estate, watching it, and handing it to someone else.

Everything on this page is free. Public data. Withholding it protects nothing.