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CVE-2026-4602

Kjur Jsrsasign vulnerability

7.5 HIGHPublic exploitEPSS 0.88%
  1. Published23 Mar 2026

Description

Versions of the package jsrsasign before 11.1.1 are vulnerable to Incorrect Conversion between Numeric Types due to handling negative exponents in ext/jsbn2.js. An attacker can force the computation of incorrect modular inverses and break signature verification by calling modPow with a negative exponent.

CVSS 3.1 breakdown

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

Affected products

Kjur Jsrsasign< 11.1.1

Remediation

Fixed in
Kjur Jsrsasign≥ 11.1.1

References

and 5 more references

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Frequently asked

Is CVE-2026-4602 being actively exploited?

CVE-2026-4602 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.88%.

How severe is CVE-2026-4602?

CVE-2026-4602 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.88% probability of exploitation.

Which products are affected by CVE-2026-4602?

Affected products include Kjur Jsrsasign.

How do I fix CVE-2026-4602?

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-2026-4602 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.