CVE-2026-43334

Bluetooth: SMP: force responder MITM requirements before building the pairing response

State: Published
Severity: 8.8 High
Published: May 8, 2026
Updated: Oct 19, 2026
Reserved: May 1, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: SMP: force responder MITM requirements before building the pairing response

smp_cmd_pairing_req() currently builds the pairing response from the initiator auth_req before enforcing the local BT_SECURITY_HIGH requirement. If the initiator omits SMP_AUTH_MITM, the response can also omit it even though the local side still requires MITM.

tk_request() then sees an auth value without SMP_AUTH_MITM and may select JUST_CFM, 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 SMP_AUTH_MITM in the response in both rsp.auth_req and auth. This keeps the responder auth bits and later method selection aligned.

Scores

CVSS	Score	Vector	Source
3.1	8.8 High	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

CWE-863 Incorrect Authorization

Affected Products

Product	Versions
LinuxLinux	2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before 425a22c5373d4e1b46492ab869074ebeeade61f3Affected 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before 7ab69426e7ecbd18a222ee2ec87ca612d30197d7Affected 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before 01bb4045d2306c266178f49ce0c3576d237a3040Affected 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before 91649c02c1baaa18cedf7fb425fa1f0f852c8183Affected 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before c8ff0ca6508535bccabd81c5c9dcc63de8a3d4fbAffected 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before fa14e0e19820b1bbdb42185c9c4efa950bcffef9Affected 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before ec17efb1ef91506cfd17a77692eaf4bbacb520eaAffected 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before d05111bfe37bfd8bd4d2dfe6675d6bdeef43f7c7Affected
LinuxLinux	3.3Affected before 3.3Not affected 5.10.253 through 5.10.Not affected 5.15.203 through 5.15.Not affected 6.1.168 through 6.1.Not affected 6.6.134 through 6.6.Not affected 6.12.81 through 6.12.Not affected 6.18.22 through 6.18.Not affected 6.19.12 through 6.19.*Not affected 7.0 and laterNot affected

Product

Versions

LinuxLinux

2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before 425a22c5373d4e1b46492ab869074ebeeade61f3Affected
2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before 7ab69426e7ecbd18a222ee2ec87ca612d30197d7Affected
2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before 01bb4045d2306c266178f49ce0c3576d237a3040Affected
2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before 91649c02c1baaa18cedf7fb425fa1f0f852c8183Affected
2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before c8ff0ca6508535bccabd81c5c9dcc63de8a3d4fbAffected
2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before fa14e0e19820b1bbdb42185c9c4efa950bcffef9Affected
2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before ec17efb1ef91506cfd17a77692eaf4bbacb520eaAffected
2b64d153a0cc9d2b60e47be013cde8490f16e0a5 to before d05111bfe37bfd8bd4d2dfe6675d6bdeef43f7c7Affected

LinuxLinux

3.3Affected
before 3.3Not affected
5.10.253 through 5.10.*Not affected
5.15.203 through 5.15.*Not affected
6.1.168 through 6.1.*Not affected
6.6.134 through 6.6.*Not affected
6.12.81 through 6.12.*Not affected
6.18.22 through 6.18.*Not affected
6.19.12 through 6.19.*Not affected
7.0 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.