CVE-2023-4147: Red Hat Enterprise Linux 9 · Use After Free
Affects Red Hat Enterprise Linux 9Source CVE Database V5
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 12:54 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 7 Aug 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
Organizations should prioritize applying official patches from Red Hat as soon as they become available to remediate this vulnerability. Until patches are deployed, restrict local user permissions to prevent unauthorized users from adding or modifying Netfilter rules, effectively limiting the attack surface. Employ strict access controls and monitoring on systems running RHEL 9 to detect suspicious local activities related to firewall rule changes. Use kernel security modules such as SELinux or AppArmor to enforce least privilege and contain potential exploitation attempts. Regularly audit user accounts and remove unnecessary local access rights. Implement comprehensive logging and alerting for Netfilter configuration changes to enable rapid detection of exploitation attempts. In environments where patching is delayed, consider isolating vulnerable systems or limiting access to trusted personnel only. Maintain up-to-date backups and incident response plans to mitigate impact in case of successful exploitation.
Description
A use-after-free flaw was found in the Linux kernel’s Netfilter functionality when adding a rule with NFTA_RULE_CHAIN_ID. This flaw allows a local user to crash or escalate their privileges on the system.
References
- access.redhat.com/errata/RHSA-2023:5069 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:5091 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:5093 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:7382 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:7389 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:7411 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2023-4147 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2225239 (opens in a new tab)
- git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0ebc1064e4874d5987722a2ddbc18f94aa53b211 (opens in a new tab)
- spinics.net/lists/stable/msg671573.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2023/10/msg00027.html (opens in a new tab)
- security.netapp.com/advisory/ntap-20231020-0006/ (opens in a new tab)
- debian.org/security/2023/dsa-5480 (opens in a new tab)
- debian.org/security/2023/dsa-5492 (opens in a new tab)