What’s Vulnerable › Vulnerabilities

CVE-2020-10185

• Severity: high (CVSS 8.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-03-05 · updated 2026-06-17
• Weakness: CWE-294

Description

The sync endpoint in YubiKey Validation Server before 2.40 allows remote attackers to replay an OTP. NOTE: this issue is potentially relevant to persons outside Yubico who operate a self-hosted OTP validation service with a non-default configuration such as an open sync pool; the issue does NOT affect YubiCloud.

Affected products

• Yubico Yubikey One Time Password Validation Server: before 2.40 — fixed in 2.40

How to fix

Upgrade to a fixed version: Yubico Yubikey One Time Password Validation Server 2.40. Check the vendor advisory for mitigations.

References

• https://github.com/Yubico/yubikey-val/releases/tag/yubikey-val-2.40
• https://lists.debian.org/debian-lts-announce/2020/03/msg00014.html
• https://www.yubico.com/support/security-advisories/ysa-2020-01/
• https://github.com/Yubico/yubikey-val/releases/tag/yubikey-val-2.40
• https://lists.debian.org/debian-lts-announce/2020/03/msg00014.html
• https://www.yubico.com/support/security-advisories/ysa-2020-01/

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