LibreSSL before 2.6.5 and 2.7.x before 2.7.4 allows a memory-cache side-channel attack on DSA and ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP
Published Jun 15, 2018
4.7
MEDIUMCVSS 3.0
EPSS 0.32%
Description
LibreSSL before 2.6.5 and 2.7.x before 2.7.4 allows a memory-cache side-channel attack on DSA and ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP. To discover a key, the attacker needs access to either the local machine or a different virtual machine on the same physical host.
Affected products
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
AV:L/AC:M/Au:N/C:P/I:N/A:N
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 (12 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.32% (0.00321) | 22.77th | v5 (v2026.06.15) |
| Sep 20, 2026 | 0.32% (0.00321) | 25.31th | v5 (v2026.06.15) |
| Jul 20, 2024 | 0.05% (0.00047) | 17.61th | v3 (v2023.03.01) |
| May 3, 2024 | 0.05% (0.00047) | 16.15th | v3 (v2023.03.01) |
| Apr 17, 2024 | 0.04% (0.00045) | 14.01th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.04% (0.00045) | 11.97th | v3 (v2023.03.01) |
| Sep 3, 2023 | 0.05% (0.00051) | 17.46th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.05% (0.00047) | 14.26th | v3 (v2023.03.01) |
| Mar 6, 2023 | 0.89% (0.00890) | 30.33th | v2 (v2022.01.01) |
| Feb 4, 2022 | 0.89% (0.00890) | 12.04th | v2 (v2022.01.01) |
| Feb 3, 2022 | 0.83% (0.00833) | 24.58th | v5 (v2026.06.15) |
| Apr 14, 2021 | 0.83% (0.00833) | 0.00th | v1 |
References (3)
- https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-2.6.5-relnotes.txt x_refsource_MISCVendor Advisory
- https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-2.7.4-relnotes.txt x_refsource_MISCVendor Advisory
- https://www.nccgroup.trust/us/our-research/technical-advisory-return-of-the-hidden-number-problem/ x_refsource_MISCThird Party Advisory
| Link | Providers | Tags |
|---|---|---|
| https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-2.6.5-relnotes.txt | x_refsource_MISCVendor Advisory | |
| https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-2.7.4-relnotes.txt | x_refsource_MISCVendor Advisory | |
| https://www.nccgroup.trust/us/our-research/technical-advisory-return-of-the-hidden-number-problem/ | x_refsource_MISCThird Party Advisory |
Change history (0)
No recorded changes yet.