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Fencer Vulns
high 7.5

CVE-2020-26557 json

Mesh Provisioning in the Bluetooth Mesh profile 1.0 and 1.0.1 may permit a nearby device (without possession of the AuthValue used in the p…

published 2021-05-24 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-19102

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 57%
public exploits
0
none known

Summary

Mesh Provisioning in the Bluetooth Mesh profile 1.0 and 1.0.1 may permit a nearby device (without possession of the AuthValue used in the provisioning protocol) to determine the AuthValue via a brute-force attack (unless the AuthValue is sufficiently random and changed each time).

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-26557 updated cvss 7.5

kernel: predictable Authvalue in Bluetooth Mesh Provisioning Leads to MITM

  • Red Hat Enterprise Linux 6 bluez, bluez-alsa, bluez-cups, bluez-libs, bluez-compat, bluez-gstreamer Red Hat Enterprise Linux 7 bluez, bluez-cups, bluez-libs, bluez-hid2hci
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 bluez, bluez-cups, bluez-libs, bluez-obexd, bluez-hid2hci Red Hat Enterprise Linux 9 bluez, bluez-cups, bluez-libs, bluez-obexd
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, kernel-alt, python-perf, +9 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.83% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 2.9 AV:A/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.