How severe is CVE-2021-38195?

CVE-2021-38195 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-38195 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-38195?

CVE-2021-38195 affects Parity Libsecp256k1. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-38195?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-38195 published?

CVE-2021-38195 was published on 2021-08-08 and last updated on 2026-06-17.

CVE-2021-38195

CVE-2021-38195 is a critical-severity vulnerability in Parity Libsecp256k1 with a CVSS 3.x base score of 9.8. 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-347.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (56th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-347
Affected product: Parity Libsecp256k1
Published: 2021-08-08
Last modified: 2026-06-17

Description

An issue was discovered in the libsecp256k1 crate before 0.5.0 for Rust. It can verify an invalid signature because it allows the R or S parameter to be larger than the curve order, aka an overflow.

Frequently asked questions

What is CVE-2021-38195?: An issue was discovered in the libsecp256k1 crate before 0.5.0 for Rust. It can verify an invalid signature because it allows the R or S parameter to be larger than the curve order, aka an overflow.
How severe is CVE-2021-38195?: CVE-2021-38195 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-38195 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-38195?: CVE-2021-38195 affects Parity Libsecp256k1. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-38195?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-38195 published?: CVE-2021-38195 was published on 2021-08-08 and last updated on 2026-06-17.

References

Affected products (1)

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

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CVE-2019-25003 — High (CVSS 7.5): An issue was discovered in the libsecp256k1 crate before 0.3.1 for Rust. Scalar::check_overflow allows a timing…
CVE-2019-20399 — Medium (CVSS 5.9): A timing vulnerability in the Scalar::check_overflow function in Parity libsecp256k1-rs before 0.3.1 potentially allows…

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