How severe is CVE-2018-12439?

CVE-2018-12439 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2018-12439 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-12439?

CVE-2018-12439 affects Matrixssl. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-12439?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-12439 published?

CVE-2018-12439 was published on 2018-06-15 and last updated on 2026-06-17.

CVE-2018-12439

CVE-2018-12439 is a medium-severity vulnerability in Matrixssl with a CVSS 3.x base score of 4.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Severity: Medium (CVSS 3.x base score 4.7)
CVSS v2: 1.9
EPSS exploit prediction: 0% (19th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Matrixssl
Published: 2018-06-15
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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. To discover an ECDSA key, the attacker needs access to either the local machine or a different virtual machine on the same physical host.
How severe is CVE-2018-12439?: CVE-2018-12439 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2018-12439 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-12439?: CVE-2018-12439 affects Matrixssl. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-12439?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-12439 published?: CVE-2018-12439 was published on 2018-06-15 and last updated on 2026-06-17.

References

https://www.nccgroup.trust/us/our-research/technical-advisory-return-of-the-hidden-number-problem/

Affected products (1)

cpe:2.3:a:matrixssl:matrixssl:*:*:*:*:*:*:*:*

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