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

> Attackers can recover private keys from DSA signatures due to a missing cryptographic step in the jsrsasign library.

- **Severity:** Critical 9.4 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:H/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Mar 2026
- **Updated:** 10 Sep 2026
- **Also known as:** GHSA-w8q8-93cx-6h7r

## 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 (Missing Cryptographic Step)

## Which versions are affected by CVE-2026-4601?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `jsrsasign` | npm | All versions | 11.1.1 |
| `jsrsasign` | npm | All versions | 11.1.1 |

Products: 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](https://insights.sbomify.com/CVE-2020-14967/): RSA PKCS#1 decryption vulnerability with prepending zeros in jsrsasign (critical 9.8)
- [CVE-2020-14968](https://insights.sbomify.com/CVE-2020-14968/): RSA-PSS signature validation vulnerability by prepending zeros in jsrsasign (critical 9.8)
- [CVE-2026-4599](https://insights.sbomify.com/CVE-2026-4599/): jsrsasign: Incomplete Comparison Allows DSA Private Key Recovery via Biased Nonce Generation (critical 9.3)
- [CVE-2026-4600](https://insights.sbomify.com/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](https://insights.sbomify.com/CVE-2021-30246/): RSA signature validation vulnerability on maleable encoded message in jsrsasign (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4601 and fix it if it is affected.

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

Affected packages and fixed versions:
- jsrsasign (npm): affected all versions; fixed in 11.1.1
- jsrsasign (npm): affected all versions; fixed in 11.1.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-4601/ (Markdown: https://insights.sbomify.com/CVE-2026-4601/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4601
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4601
- OSV: https://osv.dev/vulnerability/CVE-2026-4601

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4601/
Summaries are generated and may contain mistakes; the official description above is the record.