# CVE-2020-1026: Incorrect Calculation in the MSR JavaScript Cryptography Library

> Attackers can bypass cryptographic checks to leak private keys or forge valid signatures in the MSR JavaScript Cryptography Library.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Apr 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-9x9j-836w-8f55

## What is CVE-2020-1026?

CVE-2020-1026 is a critical vulnerability in Microsoft Research JavaScript Cryptography Library V1.4, published on 15 Apr 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A Security Feature Bypass vulnerability exists in the MSR JavaScript Cryptography Library that is caused by multiple bugs in the library’s Elliptic Curve Cryptography (ECC) implementation.An attacker could potentially abuse these bugs to learn information about a server’s private ECC key (a key leakage attack) or craft an invalid ECDSA signature that nevertheless passes as valid.The security update addresses the vulnerability by fixing the bugs disclosed in the ECC implementation, aka 'MSR JavaScript Cryptography Library Security Feature Bypass Vulnerability'.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2020-1026?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `msrcrypto` | npm | All versions | 1.5.8 |
| `msrcrypto` | npm | All versions | 1.5.8 |

Products: Microsoft Research Javascript Cryptography Library.

## How do I fix CVE-2020-1026?

Upgrade msrcrypto to 1.5.8 or later.

## Is CVE-2020-1026 being exploited?

There is no known exploitation of CVE-2020-1026 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Research JavaScript Cryptography Library V1.4

- [CVE-2018-8319](https://insights.sbomify.com/CVE-2018-8319/): Sensitive Data Exposure in msrcrypto (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-1026 and fix it if it is affected.

What it is: CVE-2020-1026 is a critical vulnerability in Microsoft Research JavaScript Cryptography Library V1.4, published on 15 Apr 2020. 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-2020-1026 in the wild and no public exploit code.

Affected packages and fixed versions:
- msrcrypto (npm): affected all versions; fixed in 1.5.8
- msrcrypto (npm): affected all versions; fixed in 1.5.8

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-2020-1026/ (Markdown: https://insights.sbomify.com/CVE-2020-1026/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-1026
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-1026
- OSV: https://osv.dev/vulnerability/CVE-2020-1026

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-1026/
Summaries are generated and may contain mistakes; the official description above is the record.