CVE-2023-4147

Privilege escalation or crash via bound-chain insertion

Published Aug 7, 2023 · Updated Feb 25, 2026

Use-after-free in Linux kernel Netfilter on RHEL 9 allows local users to gain privileges or crash the system via a crafted nftables rule. nf_tables_newrule accepts NFTA_RULE_CHAIN_ID for a bound chain and inserts a rule even though bound chains must reject direct insertion, leaving freed state reachable. A local account is required; successful exploitation grants elevated privileges or crashes the kernel, interrupting the host.

CVSS severity7.8
High
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel Netfilter on RHEL 9 allows local users to gain privileges or crash the system via a crafted nftables rule. nf_tables_newrule accepts NFTA_RULE_CHAIN_ID for a bound chain and inserts a rule even though bound chains must reject direct insertion, leaving freed state reachable. A local account is required; successful exploitation grants elevated privileges or crashes the kernel, interrupting the host.

The record

CVE
CVE-2023-4147
Published
Aug 7, 2023
Updated
Feb 25, 2026
Vendor
Red Hat
Product
Red Hat Enterprise Linux 9.0 Extended Update Support
Classifications
CWE-416, T1068, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 7, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Red Hat · Red Hat Enterprise Linux 9.0 Extended Update SupportAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.

Published CVSS scores

7.8Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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