CyberSecBulletin
CVE-2026-43018NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-43018 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions 59eecf0ffde15670e6a5e10c47be67f73d843b20, 5fb69e1eeea9d6cba80517e9f058b56b34bc3a81, 7cadb03be37e761130edb153544fe0770a842b19 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.26% 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 Linux to 59eecf0ffde15670e6a5e10c47be67f73d843b20 or 5fb69e1eeea9d6cba80517e9f058b56b34bc3a81 or 7cadb03be37e761130edb153544fe0770a842b19 or 1d0bdbfe3e91c11f0a704c52443a9446a10d699c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.1.168 or 6.6.134 or 6.12.81 or 6.18.22, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux95118dd4edfec950898a00180c6f998df0a6406d up to, but not including, 59eecf0ffde15670e6a5e10c47be67f73d843b20; 95118dd4edfec950898a00180c6f998df0a6406d up to, but not including, 5fb69e1eeea9d6cba80517e9f058b56b34bc3a81; 95118dd4edfec950898a00180c6f998df0a6406d up to, but not including, 7cadb03be37e761130edb153544fe0770a842b19; 95118dd4edfec950898a00180c6f998df0a6406d up to, but not including, 1d0bdbfe3e91c11f0a704c52443a9446a10d699c; 95118dd4edfec950898a00180c6f998df0a6406d up to, but not including, ea3cd36d7382d5f8309df04c275d20df139ed42c; 95118dd4edfec950898a00180c6f998df0a6406d up to, but not including, b255531b27da336571411248c2a72a350662bd09; 5.1759eecf0ffde15670e6a5e10c47be67f73d843b20, 5fb69e1eeea9d6cba80517e9f058b56b34bc3a81, 7cadb03be37e761130edb153544fe0770a842b19, 1d0bdbfe3e91c11f0a704c52443a9446a10d699c, ea3cd36d7382d5f8309df04c275d20df139ed42c, b255531b27da336571411248c2a72a350662bd09
LinuxLinux Kernel5.17 up to, but not including, 6.1.168; 6.2 up to, but not including, 6.6.134; 6.7 up to, but not including, 6.12.81; 6.13 up to, but not including, 6.18.22; 6.19 up to, but not including, 6.19.12; 7.06.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12

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
AdjacentThe attacker must be on the same local network segment.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: fix potential UAF in hci_le_remote_conn_param_req_evt hci_conn lookup and field access must be covered by hdev lock in hci_le_remote_conn_param_req_evt, otherwise it's possible it is freed concurrently. Extend the hci_dev_lock critical section to cover all conn usage.

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. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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