Bluetooth: SMP: derive legacy responder STK authentication from MITM state (Linux Linux)

CVE-2026-31773
HIGH 8.8

At a glance

Source
NVD
EPSS
EPSS 0.28 % · percentile 20 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

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.

Weaknesses (CWE)

  • CWE-287 — Improper Authentication

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 8.8CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 8.8CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected fff3490f47810e2d34b91fb9e31103e923b11c2f < 9a38659a3d06080715691bd3139f9c4b61f688e3 ; affected fff3490f47810e2d34b91fb9e31103e923b11c2f < 667f44f1392df6482483756458c48670e579e9ff ; affected fff3490f47810e2d34b91fb9e31103e923b11c2f < 929db734d12db41ca5f95424db4612397f1bd4a7 ; affected fff3490f47810e2d34b91fb9e31103e923b11c2f < b1c6a8e554a39b222c0879a288ea98e338fc4d77 ; affected fff3490f47810e2d34b91fb9e31103e923b11c2f < 0afc846bd80073ffcd2b8040f2b2fafaea3d9f72 ; affected fff3490f47810e2d34b91fb9e31103e923b11c2f < 061ee71ac6b03c9f8432fe49538c3682bfcf4cf3
Linux · Linuxaffected 3.16 ; unaffected 0 < 3.16 ; unaffected 5.10.253 ≤ 5.10.* ; unaffected 5.15.203 ≤ 5.15.* ; unaffected 6.1.168 ≤ 6.1.* ; unaffected 6.6.134 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD