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Fencer Vulns
medium 6.8

CVE-2018-20340 json

Yubico libu2f-host 1.1.6 contains unchecked buffers in devs.c, which could enable a malicious token to exploit a buffer overflow.

published 2019-03-17 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-12898

cvss
6.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

Yubico libu2f-host 1.1.6 contains unchecked buffers in devs.c, which could enable a malicious token to exploit a buffer overflow. An attacker could use this to attempt to execute malicious code using a crafted USB device masquerading as a security token on a computer where the affected library is currently in use. It is not possible to perform this attack with a genuine YubiKey.

Patch / fix

  • libu2f-host Debian 14, Debian 13, Debian 12 1.1.7-1

debian advisories DEBIAN-CVE-2018-20340

  • libu2f-host Ubuntu 18.04 LTS 1.1.4-1ubuntu0.1

ubuntu advisories UBUNTU-CVE-2018-20340

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libu2f-host SLE Module for Basesystem 15 SP3, SLE Module for Basesystem 15 SP2 1.1.10-3.9.1
  • libu2f-host SLES for SAP 12 SP4, SLES 12 SP4, SLED 12 SP4 1.1.6-3.5.1
  • pam_u2f SLES for SAP 12 SP4, SLES 12 SP4, SLED 12 SP4 1.0.8-3.3.1
  • libu2f-host SLE Module for Basesystem 15 1.1.6-3.3.3

suse advisories SUSE-SU-2021:1755-1SUSE-SU-2019:1749-1SUSE-SU-2019:1340-1

  • libu2f-host openSUSE Leap 15.3 1.1.10-3.9.1
  • libu2f-host openSUSE Leap 15.2 1.1.10-lp152.4.3.1
  • libu2f-host openSUSE Leap 15.1, openSUSE Leap 15.0 1.1.6-lp151.2.3.1

opensuse advisories openSUSE-SU-2021:1755-1openSUSE-SU-2021:0799-1openSUSE-SU-2019:1475-1

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 6.8 CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

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.