CVE-2026-43334

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

HIGH
8.8
CVSS Score
Published: May 8, 2026 at 01:31 PM UTC
Updated: October 19, 2026 at 08:18 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH8.8
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

3.3 ≤ v < 5.10.2535.11 ≤ v < 5.15.2035.16 ≤ v < 6.1.1686.13 ≤ v < 6.18.226.19 ≤ v < 6.19.126.2 ≤ v < 6.6.1346.7 ≤ v < 6.12.812b64d153a0cc9d2b60e47be013cde8490f16e0a53.37.07.0 rc17.0 rc27.0 rc37.0 rc47.0 rc57.0 rc6
Vendor states this is fixed in 01bb4045d2306c266178f49ce0c3576d237a3040 (fixed)
Vendor states this is fixed in 425a22c5373d4e1b46492ab869074ebeeade61f3 (fixed)
Vendor states this is fixed in 7ab69426e7ecbd18a222ee2ec87ca612d30197d7 (fixed)
Vendor states this is fixed in 91649c02c1baaa18cedf7fb425fa1f0f852c8183 (fixed)
Vendor states this is fixed in c8ff0ca6508535bccabd81c5c9dcc63de8a3d4fb (fixed)
Vendor states this is fixed in d05111bfe37bfd8bd4d2dfe6675d6bdeef43f7c7 (fixed)
Vendor states this is fixed in ec17efb1ef91506cfd17a77692eaf4bbacb520ea (fixed)
Vendor states this is fixed in fa14e0e19820b1bbdb42185c9c4efa950bcffef9 (fixed)
Vendor states this is fixed in 3.3 (unaffected)
Vendor states this is fixed in 5.10.253 (unaffected)
Vendor states this is fixed in 5.15.203 (unaffected)
Vendor states this is fixed in 6.1.168 (unaffected)
Vendor states this is fixed in 6.12.81 (unaffected)
Vendor states this is fixed in 6.18.22 (unaffected)
Vendor states this is fixed in 6.19.12 (unaffected)
Vendor states this is fixed in 6.6.134 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHLinux
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfoCWE-863

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