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VulnerabilityPublished Updated

CVE-2026-43021: Linux kernel · Bluetooth: hci_sync: fix leaks when hci_cmd_sync_queue_once fails

Affects Linux kernelSource CVE Database V5

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Not known to be exploited : upgrade to aca377208e7f7322bf4e107cdec6e7d7e8aa7a88 or 7fd74178d4b16dcf47179da634ea9d7c02e3608b when convenient.

Data as of 6 Nov 2026, 16:33 UTC

Severity
Low

Rated Low by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch
Available – fixed in aca377208e7f7322bf4e107cdec6e7d7e8aa7a88, 7fd74178d4b16dcf47179da634ea9d7c02e3608b

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 6 Nov 2026.

What to do

Upgrade Linux kernel to aca377208e7f7322bf4e107cdec6e7d7e8aa7a88 or 7fd74178d4b16dcf47179da634ea9d7c02e3608b.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ a106e50be74b0896583f4d010a69f9806e4194f4, < aca377208e7f7322bf4e107cdec6e7d7e8aa7a88
Fixed in
  • aca377208e7f7322bf4e107cdec6e7d7e8aa7a88
LinuxLinuxAffected
  • ≥ a106e50be74b0896583f4d010a69f9806e4194f4, < 7fd74178d4b16dcf47179da634ea9d7c02e3608b
Fixed in
  • 7fd74178d4b16dcf47179da634ea9d7c02e3608b
LinuxLinuxAffected
  • =6.19
Fixed in–

AI-suggested

The issue is fixed in the Linux kernel commits aca377208e7f7322bf4e107cdec6e7d7e8aa7a88 and 7fd74178d4b16dcf47179da634ea9d7c02e3608b. Applying these patches or upgrading to a kernel version that includes these fixes will remediate the vulnerability.

Description

A vulnerability in the Linux kernel Bluetooth subsystem (hci_sync) caused memory leaks when the function hci_cmd_sync_queue_once() failed, due to the destroy callback not being called. This issue has been fixed in specific Linux kernel commits.

References

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