How severe is CVE-2019-20399?

CVE-2019-20399 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2019-20399 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-20399?

CVE-2019-20399 affects Parity Libsecp256k1. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-20399?

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

When was CVE-2019-20399 published?

CVE-2019-20399 was published on 2020-01-23 and last updated on 2026-06-17.

CVE-2019-20399

CVE-2019-20399 is a medium-severity vulnerability in Parity Libsecp256k1 with a CVSS 3.x base score of 5.9. 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-203.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 1% (55th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-203
Affected product: Parity Libsecp256k1
Published: 2020-01-23
Last modified: 2026-06-17

Description

A timing vulnerability in the Scalar::check_overflow function in Parity libsecp256k1-rs before 0.3.1 potentially allows an attacker to leak information via a side-channel attack.

Frequently asked questions

What is CVE-2019-20399?: A timing vulnerability in the Scalar::check_overflow function in Parity libsecp256k1-rs before 0.3.1 potentially allows an attacker to leak information via a side-channel attack.
How severe is CVE-2019-20399?: CVE-2019-20399 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2019-20399 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-20399?: CVE-2019-20399 affects Parity Libsecp256k1. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-20399?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-20399 published?: CVE-2019-20399 was published on 2020-01-23 and last updated on 2026-06-17.

References

https://github.com/paritytech/libsecp256k1/commit/11ba23a9766a5079918cd9f515bc100bc8164b50

Affected products (1)

cpe:2.3:a:parity:libsecp256k1:*:*:*:*:*:*:*:*

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