Kernel: Use After Free
CVE-2023-4244 is a high-severity use after free vulnerability in Kernel from Linux, with a CVSS 3.1 base score of 7.0 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. The record lists versions 4.19.316, 5.4.262, 5.10.198 as the first without the flaw, so updating Kernel to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.24% 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 Kernel to 4.19.316 or 5.4.262 or 5.10.198 or 5.15.134, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.19.316 or 5.4.262 or 5.10.198 or 5.15.134, whichever matches your release line, or a later version.
- Read the advisory on git.kernel.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Kernel | before 4.19.316; 4.20 up to, but not including, 5.4.262; 5.5 up to, but not including, 5.10.198; 5.11 up to, but not including, 5.15.134; 5.16 up to, but not including, 6.1.56; 6.2 up to, but not including, 6.4.11 | 4.19.316, 5.4.262, 5.10.198, 5.15.134, 6.1.56, 6.4.11 |
| Linux | Linux Kernel | before 4.19.316; 4.20 up to, but not including, 5.4.262; 5.5 up to, but not including, 5.10.198; 5.11 up to, but not including, 5.15.134; 5.16 up to, but not including, 6.1.56; 6.2.0 up to, but not including, 6.4.11 | 4.19.316, 5.4.262, 5.10.198, 5.15.134, 6.1.56, 6.4.11 |
| Debian | Debian Linux | 10.0 | 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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/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 (google.com) |
| CVSS 3.1 | 7.0 | High | NVD |
Official description
A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. Due to a race condition between nf_tables netlink control plane transaction and nft_set element garbage collection, it is possible to underflow the reference counter causing a use-after-free vulnerability. We recommend upgrading past commit 3e91b0ebd994635df2346353322ac51ce84ce6d8.
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.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2023/10/msg00027.htmlMailing List, Third Party Advisory
- lists.debian.org/debian-lts-announce/2024/01/msg00004.htmlMailing List, Third Party Advisory
Other vulnerabilities in Kernel
- 7.1 High severity
- 7.8 High severity
Linux Kernel Use-After-Free Exploited
- 7.8 High severity
- 7.1 High severity
- 7.4 High severity
- 7.0 High severity
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.