The sync endpoint in YubiKey Validation Server before 2.40 allows remote attackers to replay an OTP
Published Mar 5, 2020
8.6
HIGHCVSS 3.1
EPSS 1.45%
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
No data.
- < 2.40
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
No CVSS v3.0 score for this CVE.
AV:N/AC:M/Au:N/C:P/I:P/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
Percentile over time
- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
Table of values (13 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 1.45% (0.01450) | 72.42th | v5 (v2026.06.15) |
| Sep 20, 2026 | 1.45% (0.01450) | 72.20th | v5 (v2026.06.15) |
| Jul 20, 2024 | 0.69% (0.00689) | 80.33th | v3 (v2023.03.01) |
| May 3, 2024 | 0.69% (0.00689) | 79.99th | v3 (v2023.03.01) |
| Dec 24, 2023 | 0.69% (0.00689) | 77.93th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.49% (0.00486) | 72.27th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.14% (0.01136) | 59.45th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.14% (0.01136) | 56.27th | v2 (v2022.01.01) |
| Feb 4, 2022 | 5.74% (0.05736) | 77.22th | v2 (v2022.01.01) |
| Feb 3, 2022 | 4.53% (0.04526) | 76.76th | v1 |
| Jan 6, 2022 | 4.53% (0.04526) | 76.54th | v1 |
| Jan 5, 2022 | 1.05% (0.01046) | 66.20th | v5 (v2026.06.15) |
| Apr 14, 2021 | 1.05% (0.01046) | 0.00th | v1 |
References (3)
- https://github.com/Yubico/yubikey-val/releases/tag/yubikey-val-2.40 x_refsource_MISCRelease NotesThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/03/msg00014.html mailing-listx_refsource_MLIST
- https://www.yubico.com/support/security-advisories/ysa-2020-01/ x_refsource_MISCExploitVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| https://github.com/Yubico/yubikey-val/releases/tag/yubikey-val-2.40 | x_refsource_MISCRelease NotesThird Party Advisory | |
| https://lists.debian.org/debian-lts-announce/2020/03/msg00014.html | mailing-listx_refsource_MLIST | |
| https://www.yubico.com/support/security-advisories/ysa-2020-01/ | x_refsource_MISCExploitVendor Advisory |
Change history (0)
No recorded changes yet.