CVE-2018-20340

MEDIUMNVD 6.86.8—
EchelonGraph scoreMEDIUM confidence

Score 6.8 from GitHub Security Advisory published 2022-05-13. NVD baseline CVSS 6.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.8
EG Score
6.8(medium)
EPSS
39.2%
KEV
Not listed

Published

March 21, 2019

Last Modified

November 21, 2024

References (12)

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 52× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-06 16:24 UTCEPSS rescore
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  7. 2026-07-03 15:56 UTCOSV refresh
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  1. 2026-06-22 14:23 UTCEPSS rescore
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  15. 2026-06-15 05:13 UTCOSV refresh
  16. 2026-06-14 23:15 UTCEPSS rescore
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  18. 2026-06-13 22:58 UTCEPSS rescore
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  40. 2026-05-31 00:14 UTCEPSS rescore
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  42. 2026-05-29 13:41 UTCEPSS rescore
  43. 2026-05-28 13:42 UTCEPSS rescore
  44. 2026-05-28 13:42 UTCEPSS rescore
  45. 2026-05-27 21:40 UTCEG score recompute
  46. 2026-05-27 21:40 UTCGHSA enrichment
  47. 2026-05-27 13:38 UTCEPSS rescore
  48. 2026-05-27 13:38 UTCEPSS rescore
  49. 2026-05-26 13:42 UTCEPSS rescore
  50. 2026-05-26 13:42 UTCEPSS rescore
  51. 2026-05-26 13:41 UTCOSV refresh
  52. 2026-05-26 07:17 UTCEPSS rescore
  53. 2026-05-26 07:17 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2018-20340?
CVE-2018-20340 is a medium vulnerability published on March 21, 2019. 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…
When was CVE-2018-20340 disclosed?
CVE-2018-20340 was first published in the National Vulnerability Database on March 21, 2019, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-20340 actively exploited?
CVE-2018-20340 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 39.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2018-20340?
CVE-2018-20340 has a CVSS v3 base score of 6.8 (NVD).
How do I remediate CVE-2018-20340?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-20340, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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