Red Hat Enterprise Linux 9: Use After Free
CVE-2023-4147 is a high-severity use after free vulnerability in Red Hat Enterprise Linux 9 from Red Hat, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.55% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux Kernel to 5.10.190 or 5.15.124 or 6.1.43 or 6.4.8, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.0 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Linux | Linux Kernel | 5.9 up to, but not including, 5.10.190; 5.11 up to, but not including, 5.15.124; 5.16 up to, but not including, 6.1.43; 6.2 up to, but not including, 6.4.8; 6.5 | 5.10.190, 5.15.124, 6.1.43, 6.4.8 |
| Fedora Project | Fedora | 38 | Not stated |
| Red Hat | Enterprise Linux | 9.0 | Not stated |
| Red Hat | Enterprise Linux EUS | 9.2 | Not stated |
| Red Hat | Enterprise Linux For Real Time | 9.0 | Not stated |
| Red Hat | Enterprise Linux For Real Time For Nfv | 9.0 | Not stated |
| Red Hat | Enterprise Linux Server AUS | 9.2 | Not stated |
| Debian | Debian Linux | 10.0; 11.0; 12.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.8 | High | NVD |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- access.redhat.com/security/cve/CVE-2023-4147Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2225239Issue Tracking, Third Party Advisory
- git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0ebc1064e4874d5987722a2ddbc18f94aa53b211Mailing List
- spinics.net/lists/stable/msg671573.htmlMailing List
Third-party and government advisories
- access.redhat.com/errata/RHSA-2023:5069Third Party Advisory
- access.redhat.com/errata/RHSA-2023:5091Third Party Advisory
- access.redhat.com/errata/RHSA-2023:5093Third Party Advisory
- access.redhat.com/errata/RHSA-2023:7382Third Party Advisory
- access.redhat.com/errata/RHSA-2023:7389Third Party Advisory
- access.redhat.com/errata/RHSA-2023:7411Third Party Advisory
Other references
Other vulnerabilities in Red Hat Enterprise Linux 9
- 7.5 High severity
- 7.5 High severity
- 7.9 High severity
- 7.3 High severity
- 7.5 High severity
- 7.8 High severity
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 8.8 High severity
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