CVE-2026-43334: Bluetooth: SMP: force responder MITM requirements before building the pairing response
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: SMP: force responder MITM requirements before building the pairing response
smpcmdpairingreq() currently builds the pairing response from the initiator authreq before enforcing the local BTSECURITYHIGH requirement. If the initiator omits SMPAUTHMITM, the response can also omit it even though the local side still requires MITM.
tkrequest() then sees an auth value without SMPAUTHMITM and may select JUSTCFM, making method selection inconsistent with the pairing policy the responder already enforces.
When the local side requires HIGH security, first verify that MITM can be achieved from the IO capabilities and then force SMPAUTHMITM in the response in both rsp.authreq and auth. This keeps the responder auth bits and later method selection aligned.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-43334?
CVE-2026-43334 has been classified as a medium severity vulnerability.
How do I fix CVE-2026-43334?
To remediate CVE-2026-43334, update your Linux kernel to the latest available version that includes the patch for this vulnerability.
What systems are affected by CVE-2026-43334?
CVE-2026-43334 affects the Linux kernel, specifically versions that utilize Bluetooth functionalities.
What is the impact of CVE-2026-43334?
The impact of CVE-2026-43334 includes potential man-in-the-middle (MITM) attacks during Bluetooth pairing processes.
When was CVE-2026-43334 disclosed?
CVE-2026-43334 was disclosed in October 2026.