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CVE-2026-4599

Kjur Jsrsasign vulnerability

9.1 CRITICALPublic exploitEPSS 0.78%
  1. Published23 Mar 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

Kjur Jsrsasign≥ 7.0.0 < 11.1.1

Remediation

Fixed in
Kjur Jsrsasign≥ 11.1.1

Frequently asked

Is CVE-2026-4599 being actively exploited?

CVE-2026-4599 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.78%.

How severe is CVE-2026-4599?

CVE-2026-4599 has a CVSS 3.1 base score of 9.1, rated critical. EPSS estimates a 0.78% probability of exploitation.

Which products are affected by CVE-2026-4599?

Affected products include Kjur Jsrsasign.

How do I fix CVE-2026-4599?

Upgrade affected software to a fixed version, for example Kjur Jsrsasign 11.1.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-4599 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.