Jsrsasign is a free open source JavaScript cryptographic library that supports a wide variety of cryptographic algorithms and standards. It is commonly used in web applications and Node.js environments to implement security features such as digital signatures, encryption, and certificate handling.

What are the risks of using vulnerable versions of jsrsasign?

Using vulnerable versions of jsrsasign can expose applications to various security risks, including private key recovery, signature forgery, and denial-of-service attacks. An attacker could potentially compromise sensitive data, impersonate users, or disrupt application availability.

How do I update jsrsasign to the latest version?

You can update jsrsasign to the latest version using the npm package manager. Run the command `npm update jsrsasign` in your project directory to update the package to the latest available version, which includes the necessary security fixes.

What versions of jsrsasign are affected by these vulnerabilities?

These vulnerabilities affect jsrsasign versions prior to 11.1.1. It is crucial to update to version 11.1.1 or later to mitigate the risks associated with these security flaws.

Multiple jsrsasign Vulnerabilities Lead to Key Recovery and DoS

Multiple vulnerabilities have been discovered in the jsrsasign library, potentially leading to private key recovery, signature forgery, and denial-of-service (DoS) attacks. These issues affect applications using jsrsasign versions prior to 11.1.1. A patch is now available to address these vulnerabilities.

These vulnerabilities range from medium to critical, potentially allowing for complete system compromise.

What is Jsrsasign?

Jsrsasign is a JavaScript cryptographic library, often used in Node.js environments, that provides implementations of various cryptographic standards and algorithms, including those related to digital signatures and certificate handling. It is used to implement public key infrastructure (PKI) in web applications. To learn more, search all jsrsasign CVEs.

CVE-2026-4599: DSA Private Key Recovery via Biased Nonce Generation

CVSS9.1

Affected versionsJsrsasign versions from 7.0.0 up to, but not including, 11.1.1 are affected.

Critical severity due to potential for private key recovery.

EPSS score of 0.037 indicates a low probability of exploitation.

An incomplete comparison in `getRandomBigIntegerZeroToMax` and `getRandomBigIntegerMinToMax` functions can lead to biased DSA nonce generation. An attacker can exploit this to recover the private key by analyzing the biased nonces used during signature generation.

How to fix CVE-2026-4599 in jsrsasign

Patch immediately

1.Update the jsrsasign package to version 11.1.1 or later.

Update jsrsasign

npm update jsrsasign

Workaround: There is no workaround; patching is the only solution.

NextGuard automatically flags CVE-2026-4599 if jsrsasign appears in any of your monitored projects — no manual lookup required.

CVE-2026-4600: DSA Signature Forgery via Domain-Parameter Validation

CVSS7.4

Affected versionsJsrsasign versions before 11.1.1 are vulnerable.

High severity due to potential for signature forgery.

EPSS score of 0.01 indicates a very low probability of exploitation.

Improper verification of cryptographic signatures in `KJUR.crypto.DSA.setPublic` allows for DSA signature forgery. An attacker can forge signatures or X.509 certificates by supplying malicious domain parameters.

How to fix CVE-2026-4600 in jsrsasign

Patch immediately

1.Update the jsrsasign package to version 11.1.1 or later.

Update jsrsasign

npm update jsrsasign

Workaround: There is no workaround; patching is the only solution.

NextGuard automatically flags CVE-2026-4600 if jsrsasign appears in any of your monitored projects — no manual lookup required.

CVE-2026-4602: Signature Verification Bypass via Negative Exponent Handling

CVSS7.5

Affected versionsJsrsasign versions before 11.1.1 are vulnerable.

High severity due to potential for signature verification bypass.

EPSS score of 0.051 indicates a low probability of exploitation.

Incorrect conversion between numeric types when handling negative exponents can lead to signature verification bypass. An attacker can force the computation of incorrect modular inverses and break signature verification by calling `modPow` with a negative exponent.

How to fix CVE-2026-4602 in jsrsasign

Patch immediately

1.Update the jsrsasign package to version 11.1.1 or later.

Update jsrsasign

npm update jsrsasign

Workaround: There is no workaround; patching is the only solution.

NextGuard automatically flags CVE-2026-4602 if jsrsasign appears in any of your monitored projects — no manual lookup required.

CVE-2026-4601: Private Key Extraction via Missing Cryptographic Validation

CVSS8.7

Affected versionsJsrsasign versions before 11.1.1 are vulnerable.

High severity due to potential for private key extraction.

EPSS score of 0.015 indicates a very low probability of exploitation.

Missing cryptographic validation during DSA signing enables private key extraction. An attacker can recover the private key by forcing `r` or `s` to be zero, causing the library to emit an invalid signature without retrying, and then solving for `x` from the resulting signature.

How to fix CVE-2026-4601 in jsrsasign

Patch immediately

1.Update the jsrsasign package to version 11.1.1 or later.

Update jsrsasign

npm update jsrsasign

Workaround: There is no workaround; patching is the only solution.

NextGuard automatically flags CVE-2026-4601 if jsrsasign appears in any of your monitored projects — no manual lookup required.

CVE-2026-4603: Deterministic Zero Output in RSA Operations via Division by Zero

CVSS5.9

Affected versionsJsrsasign versions before 11.1.1 are vulnerable.

Medium severity due to potential for RSA operation manipulation.

EPSS score of 0.009 indicates a very low probability of exploitation.

Division by zero allows an invalid JWK modulus to cause deterministic zero output in RSA operations. An attacker can force RSA public-key operations to collapse to deterministic zero outputs and hide “invalid key” errors by supplying a JWK whose modulus decodes to zero.

How to fix CVE-2026-4603 in jsrsasign

Patch within 7 days

1.Update the jsrsasign package to version 11.1.1 or later.

Update jsrsasign

npm update jsrsasign

Workaround: There is no workaround; patching is the only solution.

NextGuard automatically flags CVE-2026-4603 if jsrsasign appears in any of your monitored projects — no manual lookup required.

CVE-2026-4598: Denial of Service via Infinite Loop

CVSS7.5

Affected versionsJsrsasign versions before 11.1.1 are vulnerable.

High severity due to potential for denial of service.

EPSS score of 0.051 indicates a low probability of exploitation.

The `bnModInverse` function is vulnerable to an infinite loop when processing zero or negative inputs. An attacker can hang the process permanently by supplying such crafted values, leading to a denial-of-service condition.

How to fix CVE-2026-4598 in jsrsasign

Patch immediately

1.Update the jsrsasign package to version 11.1.1 or later.

Update jsrsasign

npm update jsrsasign

Workaround: Ensure that inputs to `bnModInverse` are validated to be positive and non-zero.

NextGuard automatically flags CVE-2026-4598 if jsrsasign appears in any of your monitored projects — no manual lookup required.

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Frequently asked questions

Multiple vulnerabilities in jsrsasign have been identified and patched in version 11.1.1. It is crucial to update to the latest version to mitigate potential risks. See all nodejs vulnerabilities.