CVE-2026-31773 | BDVDB-2026-329977 Detail
LinuxLinux
Description#
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: SMP: derive legacy responder STK authentication from MITM state The legacy responder path in smp_random() currently labels the stored STK as authenticated whenever pending_sec_level is BT_SECURITY_HIGH. That reflects what the local service requested, not what the pairing flow actually achieved. For Just Works/Confirm legacy pairing, SMP_FLAG_MITM_AUTH stays clear and the resulting STK should remain unauthenticated even if the local side requested HIGH security. Use the established MITM state when storing the responder STK so the key metadata matches the pairing result. This also keeps the legacy path aligned with the Secure Connections code, which already treats JUST_WORKS/JUST_CFM as unauthenticated.
Impact#
Per CVSS v3.1: confidentiality impact high, integrity impact high, availability impact high. Attack vector: adjacent.
Weaknesses#
- CWE-287 Improper Authentication
References#
- https://git.kernel.org/stable/c/9a38659a3d06080715691bd3139f9c4b61f688e3
- https://git.kernel.org/stable/c/667f44f1392df6482483756458c48670e579e9ff
- https://git.kernel.org/stable/c/929db734d12db41ca5f95424db4612397f1bd4a7
- https://git.kernel.org/stable/c/b1c6a8e554a39b222c0879a288ea98e338fc4d77
- https://git.kernel.org/stable/c/0afc846bd80073ffcd2b8040f2b2fafaea3d9f72
- https://git.kernel.org/stable/c/061ee71ac6b03c9f8432fe49538c3682bfcf4cf3
- https://git.kernel.org/stable/c/9a6d0db176f082685e0b6149700c0baf3ce2aa8b
- https://git.kernel.org/stable/c/20756fec2f0108cb88e815941f1ffff88dc286fe
Exploit#
No public exploit known
History#
- Version 1Record published in the CVE List.
- Version 2Most recent update recorded in the CVE List.