How severe is CVE-2020-14966?

CVE-2020-14966 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2020-14966 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-14966?

CVE-2020-14966 primarily affects Kjur Jsrsasign. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-14966?

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

When was CVE-2020-14966 published?

CVE-2020-14966 was published on 2020-06-22 and last updated on 2026-06-22.

CVE-2020-14966

CVE-2020-14966 is a high-severity vulnerability in Kjur Jsrsasign with a CVSS 3.x base score of 7.5. 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: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-347
Affected product: Kjur Jsrsasign
Published: 2020-06-22
Last modified: 2026-06-22

Description

An issue was discovered in the jsrsasign package through 8.0.18 for Node.js. It allows a malleability in ECDSA signatures by not checking overflows in the length of a sequence and '0' characters appended or prepended to an integer. The modified signatures are verified as valid. This could have a security-relevant impact if an application relied on a single canonical signature.

Frequently asked questions

What is CVE-2020-14966?: An issue was discovered in the jsrsasign package through 8.0.18 for Node.js. It allows a malleability in ECDSA signatures by not checking overflows in the length of a sequence and '0' characters appended or prepended to an integer. The modified signatures are verified as valid. This could have a security-relevant impact if an application relied on a single canonical signature.
How severe is CVE-2020-14966?: CVE-2020-14966 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2020-14966 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-14966?: CVE-2020-14966 primarily affects Kjur Jsrsasign. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-14966?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-14966 published?: CVE-2020-14966 was published on 2020-06-22 and last updated on 2026-06-22.

References

Affected products (2)

cpe:2.3:a:kjur:jsrsasign:*:*:*:*:*:node.js:*:*
cpe:2.3:a:netapp:max_data:-:*:*:*:*:*:*:*

More vulnerabilities in Kjur Jsrsasign

CVE-2020-14968 — Critical (CVSS 9.8): An issue was discovered in the jsrsasign package before 8.0.17 for Node.js. Its RSASSA-PSS (RSA-PSS) implementation…
CVE-2020-14967 — Critical (CVSS 9.8): An issue was discovered in the jsrsasign package before 8.0.18 for Node.js. Its RSA PKCS1 v1.5 decryption…
CVE-2026-4599 — Critical (CVSS 9.1): Versions of the package jsrsasign from 7.0.0 and before 11.1.1 are vulnerable to Incomplete Comparison with Missing…
CVE-2021-30246 — Critical (CVSS 9.1): In the jsrsasign package through 10.1.13 for Node.js, some invalid RSA PKCS#1 v1.5 signatures are mistakenly recognized…
CVE-2026-4601 — High (CVSS 8.7): Versions of the package jsrsasign before 11.1.1 are vulnerable to Missing Cryptographic Step via the…
CVE-2022-25898 — High (CVSS 7.7): The package jsrsasign before 10.5.25 are vulnerable to Improper Verification of Cryptographic Signature when JWS or JWT…

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