CVE-2020-10185
The sync endpoint in YubiKey Validation Server before 2.40 allows remote attackers to replay an OTP.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.68%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.6 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
- EPSS
- 1.68% probability · 77th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-294
- Affected
- yubico/yubikey one time password validation server
- Source
- cve@mitre.org
EPSS 1.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/Yubico/yubikey-val/releases/tag/yubikey-val-2.40Release Notes, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/03/msg00014.html
- https://www.yubico.com/support/security-advisories/ysa-2020-01/Exploit, Vendor Advisory
- https://github.com/Yubico/yubikey-val/releases/tag/yubikey-val-2.40Release Notes, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/03/msg00014.html
- https://www.yubico.com/support/security-advisories/ysa-2020-01/Exploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.