CVE-2026-4601 jsrsasign: Missing cryptographic validation during DSA signing enables private key extraction

What is CVE-2026-4601?

CVE-2026-4601 is a critical vulnerability in jsrsasign, published on 23 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Versions of the package jsrsasign before 11.1.1 are vulnerable to Missing Cryptographic Step via the KJUR.crypto.DSA.signWithMessageHash process in the DSA signing implementation. An attacker can recover the private key by forcing r or s to be zero, so the library emits an invalid signature without retrying, and then solves for x from the resulting signature.

Weakness: CWE-325

Which versions are affected by CVE-2026-4601?

2 open source packages ship an affected version, including jsrsasign. It affects 1 product.

Products include Kjur Jsrsasign.

How do I fix CVE-2026-4601?

Upgrade jsrsasign to 11.1.1 or later.

Is CVE-2026-4601 being exploited?

There is no known exploitation of CVE-2026-4601 in the wild and no public exploit code.

Other vulnerabilities in jsrsasign

• CVE-2020-14967 RSA PKCS#1 decryption vulnerability with prepending zeros in jsrsasign Critical 9.8
• CVE-2020-14968 RSA-PSS signature validation vulnerability by prepending zeros in jsrsasign Critical 9.8
• CVE-2026-4599 jsrsasign: Incomplete Comparison Allows DSA Private Key Recovery via Biased Nonce Generation Critical 9.3
• CVE-2026-4600 jsrsasign: DSA signatures or X.509 certificates can be forged via DSA domain-parameter validation in KJUR.crypto.DSA.setPublic Critical 9.1
• CVE-2021-30246 RSA signature validation vulnerability on maleable encoded message in jsrsasign Critical 9.1

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-w8q8-93cx-6h7r.