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CVE-2026-31773

8.8 · HIGH

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…

Published May 1, 2026EPSS 0.28%

Overview

CVE-2026-31773 is a high-severity vulnerability. It was published on May 1, 2026 and has a CVSS 3.1 base score of 8.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/061ee71ac6b03c9f8432fe49538c3682bfcf4cf3Refgit.kernel.org/stable/c/0afc846bd80073ffcd2b8040f2b2fafaea3d9f72Refgit.kernel.org/stable/c/20756fec2f0108cb88e815941f1ffff88dc286feRefgit.kernel.org/stable/c/667f44f1392df6482483756458c48670e579e9ffRefgit.kernel.org/stable/c/929db734d12db41ca5f95424db4612397f1bd4a7Refgit.kernel.org/stable/c/9a38659a3d06080715691bd3139f9c4b61f688e3Refgit.kernel.org/stable/c/9a6d0db176f082685e0b6149700c0baf3ce2aa8bRefgit.kernel.org/stable/c/b1c6a8e554a39b222c0879a288ea98e338fc4d77

How CyberStrike helps

Frequently asked questions

What is CVE-2026-31773?

CVE-2026-31773 is a high-severity vulnerability. It was published on May 1, 2026 and has a CVSS 3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-31773?

This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-31773?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-31773?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-31773 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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