Bug 2464455 (CVE-2026-43020)

Summary: CVE-2026-43020 kernel: Bluetooth: MGMT: validate LTK enc_size on load
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Bluetooth management (MGMT) component. An attacker could exploit a vulnerability in how Long Term Keys (LTK) are loaded. By providing an oversized encryption size, a stack buffer overflow can occur, potentially leading to a denial of service.
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Description OSIDB Bzimport 2026-05-01 15:07:45 UTC 
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: MGMT: validate LTK enc_size on load

Load Long Term Keys stores the user-provided enc_size and later uses
it to size fixed-size stack operations when replying to LE LTK
requests. An enc_size larger than the 16-byte key buffer can therefore
overflow the reply stack buffer.

Reject oversized enc_size values while validating the management LTK
record so invalid keys never reach the stored key state.
Comment 1 Keith Grant 2026-05-01 16:49:05 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050157-CVE-2026-43020-3561@gregkh/T
Comment 3 errata-xmlrpc 2026-05-28 01:19:59 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:21557 https://access.redhat.com/errata/RHSA-2026:21557
Comment 4 errata-xmlrpc 2026-05-28 01:24:03 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:21556 https://access.redhat.com/errata/RHSA-2026:21556
Comment 5 errata-xmlrpc 2026-05-28 08:26:02 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:21706 https://access.redhat.com/errata/RHSA-2026:21706
Comment 6 errata-xmlrpc 2026-05-28 13:26:29 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:21745 https://access.redhat.com/errata/RHSA-2026:21745