CyberSecBulletin
CVE-2023-4015NVD status: Modified

Kernel: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2023-4015 is a high-severity use after free vulnerability in Kernel from Linux, 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. The record lists version 6.5 as the first without the flaw, so updating Kernel to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.29% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Kernel to 6.5 or a later version.
  2. Update SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to V1.1 or a later version.
  3. 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.
  4. Read the advisory on git.kernel.org for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxKernel6.4 up to, but not including, 6.56.5
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystembefore V1.1V1.1
LinuxLinux Kernel5.9 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, 6.4.85.10.190, 5.15.124, 6.1.43, 6.4.8
DebianDebian Linux12.0Not 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 systemScoreSeverityScored by
CVSS 3.17.8HighCNA (google.com)
CVSS 3.17.8HighNVD

Official description

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. On an error when building a nftables rule, deactivating immediate expressions in nft_immediate_deactivate() can lead unbinding the chain and objects be deactivated but later used. We recommend upgrading past commit 0a771f7b266b02d262900c75f1e175c7fe76fec2.

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.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in Kernel

All Kernel vulnerabilities

Recent Use After Free vulnerabilities

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