CVE-2018-12439 — MatrixSSL through 3.9.5 Open allows a memory-cache side-channel attack on ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP

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MEDIUM

MatrixSSL through 3.9.5 Open allows a memory-cache side-channel attack on ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP

Published Jun 15, 2018

4.7

MEDIUM

CVSS 3.0

EPSS 0.27%

Description

MatrixSSL through 3.9.5 Open allows a memory-cache side-channel attack on ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP. To discover an ECDSA 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

0.27% 0.00275

Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.

EPSS probability 0.00275

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 (10 key points)

Flat stretches are collapsed; showing up to 120 newest points.

Date	Score	Percentile	Model
Oct 1, 2026	0.27% (0.00275)	17.99th	v5 (v2026.06.15)
Sep 20, 2026	0.27% (0.00275)	20.13th	v5 (v2026.06.15)
Jul 20, 2024	0.04% (0.00044)	12.95th	v3 (v2023.03.01)
Apr 25, 2024	0.04% (0.00044)	11.68th	v3 (v2023.03.01)
Feb 8, 2024	0.04% (0.00043)	6.67th	v3 (v2023.03.01)
Mar 7, 2023	0.04% (0.00044)	10.26th	v3 (v2023.03.01)
Mar 6, 2023	0.89% (0.00885)	27.89th	v2 (v2022.01.01)
Feb 4, 2022	0.89% (0.00885)	10.50th	v2 (v2022.01.01)
Feb 3, 2022	0.42% (0.00416)	10.04th	v5 (v2026.06.15)
Apr 14, 2021	0.42% (0.00416)	0.00th	v1