How severe is CVE-2026-4599?

CVE-2026-4599 has a CVSS 3.x base score of 9.1, 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 none.

Is CVE-2026-4599 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-4599?

CVE-2026-4599 affects Kjur Jsrsasign. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-4599?

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.

Does CVE-2026-4599 have an EU (EUVD) identifier?

Yes. CVE-2026-4599 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14373.

When was CVE-2026-4599 published?

CVE-2026-4599 was published on 2026-03-23 and last updated on 2026-07-01.

CVE-2026-4599

CVE-2026-4599 is a critical-severity vulnerability in Kjur Jsrsasign with a CVSS 3.x base score of 9.1. 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-1023.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v4: 9.3
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-14373
Weakness: CWE-1023
Affected product: Kjur Jsrsasign
Published: 2026-03-23
Last modified: 2026-07-01

Description

Versions of the package jsrsasign from 7.0.0 and before 11.1.1 are vulnerable to Incomplete Comparison with Missing Factors via the getRandomBigIntegerZeroToMax and getRandomBigIntegerMinToMax functions in src/crypto-1.1.js; an attacker can recover the private key by exploiting the incorrect compareTo checks that accept out-of-range candidates and thus bias DSA nonces during signature generation.

Frequently asked questions

What is CVE-2026-4599?: Versions of the package jsrsasign from 7.0.0 and before 11.1.1 are vulnerable to Incomplete Comparison with Missing Factors via the getRandomBigIntegerZeroToMax and getRandomBigIntegerMinToMax functions in src/crypto-1.1.js; an attacker can recover the private key by exploiting the incorrect compareTo checks that accept out-of-range candidates and thus bias DSA nonces during signature generation.
How severe is CVE-2026-4599?: CVE-2026-4599 has a CVSS 3.x base score of 9.1, 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 none.
Is CVE-2026-4599 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-4599?: CVE-2026-4599 affects Kjur Jsrsasign. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-4599?: 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.
Does CVE-2026-4599 have an EU (EUVD) identifier?: Yes. CVE-2026-4599 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14373.
When was CVE-2026-4599 published?: CVE-2026-4599 was published on 2026-03-23 and last updated on 2026-07-01.

References

Affected products (1)

cpe:2.3:a:kjur:jsrsasign:*:*:*:*:*:node.js:*:*

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-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…
CVE-2026-4602 — High (CVSS 7.5): Versions of the package jsrsasign before 11.1.1 are vulnerable to Incorrect Conversion between Numeric Types due to…

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