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CVE-2018-12439

17
FAUCET Score

CVE-2018-12439 describes a memory-cache side-channel vulnerability in MatrixSSL versions through 3.9.5, allowing for an ECDSA key recovery attack known as the Return Of the Hidden Number Problem (ROHNP). This vulnerability has a CVSS score of 4.7 (Medium), indicating a local attack vector with high attack complexity, requiring an attacker to have access to the local machine or a different virtual machine on the same physical host to achieve high confidentiality impact. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 3.9.5CPE matchmatch criteria
cpe:2.3:a:matrixssl:matrixssl:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

4.7MEDIUM

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
1.0
Impact Score
3.6
CvssVersion
3.0

Exploit Intelligence

EPSS Score
0.27%
Probability of exploitation in next 30 days
EPSS Percentile
19.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0027 is in the 62nd percentile among its peer group of 1,297 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.4 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

nccgroup.trust / us/our-research/technical-advisory-return-of-the-hidden-number-problem
Third Party Advisory