What is CVE-2021-41117?

CVE-2021-41117 is a high-severity security vulnerability in keypair (npm), affecting versions < 1.0.4. It is fixed in 1.0.4.

How severe is CVE-2021-41117?

CVE-2021-41117 has a CVSS score of 8.7 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of keypair are affected by CVE-2021-41117?

keypair (npm) versions < 1.0.4 is affected.

Is there a fix for CVE-2021-41117?

Yes. CVE-2021-41117 is fixed in 1.0.4. Upgrade to this version or later.

Is CVE-2021-41117 exploitable, and should I be worried?

Whether CVE-2021-41117 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2021-41117 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2021-41117?

Upgrade keypair to 1.0.4 or later.

CVE-2021-41117 in keypair

Q: How severe is CVE-2021-41117?

CVE-2021-41117 has a CVSS score of 8.7 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of keypair are affected by CVE-2021-41117?

keypair (npm) versions < 1.0.4 is affected.

Q: Is there a fix for CVE-2021-41117?

Yes. CVE-2021-41117 is fixed in 1.0.4. Upgrade to this version or later.

Q: Is CVE-2021-41117 exploitable, and should I be worried?

Whether CVE-2021-41117 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2021-41117 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2021-41117?

Upgrade keypair to 1.0.4 or later.

Summary

Insecure random number generation in keypair

Description and Impact

A bug in the pseudo-random number generator used by keypair versions up to and including 1.0.3 could allow for weak RSA key generation. This could enable an attacker to decrypt confidential messages or gain authorized access to an account belonging to the victim. We recommend replacing any RSA keys that were generated using keypair version 1.0.3 or earlier.

Additional Details

The specific line with the flaw is:

b.putByte(String.fromCharCode(next & 0xFF))

The definition of putByte is

util.ByteBuffer.prototype.putByte = function(b) {
  this.data += String.fromCharCode(b);
};

Simplified, this is String.fromCharCode(String.fromCharCode(next & 0xFF)). This results in most of the buffer containing zeros. An example generated buffer:

(Note: truncated for brevity)

\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00
\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00
\x00\x00\x00\x00\x04\x00\x00\x00....\x00\x00\x00\x00\x00\x00\x00\x00\x00
\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00
\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00

Since it is masking with 0xFF, approximately 97% of the bytes are converted to zeros. The impact is that each byte in the RNG seed has a 97% chance of being 0 due to incorrect conversion.

Credit

This issue was reported to GitHub Security Lab by Ross Wheeler of Axosoft. It was discovered by Axosoft engineer Dan Suceava, who noticed that keypair was regularly generating duplicate RSA keys. GitHub security engineer @vcsjones (Kevin Jones) independently investigated the problem and identified the cause and source code location of the bug.

Impact

CVE-2021-41117 has a CVSS score of 8.7 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.0.4); upgrading removes the vulnerable code path.

Affected versions

keypair (< 1.0.4)

Security releases

keypair → 1.0.4 (npm)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

Already deployed Kodem?

See it in your environment New to Kodem? Get a demo →

Remediation advice

The bug in the pseudo-random number generator is fixed in commit 9596418.
If the crypto module is available, it is used instead of the pseudo-random number generator. Also fixed in 9596418

Frequently Asked Questions

What is CVE-2021-41117? CVE-2021-41117 is a high-severity security vulnerability in keypair (npm), affecting versions < 1.0.4. It is fixed in 1.0.4.
How severe is CVE-2021-41117? CVE-2021-41117 has a CVSS score of 8.7 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of keypair are affected by CVE-2021-41117? keypair (npm) versions < 1.0.4 is affected.
Is there a fix for CVE-2021-41117? Yes. CVE-2021-41117 is fixed in 1.0.4. Upgrade to this version or later.
Is CVE-2021-41117 exploitable, and should I be worried? Whether CVE-2021-41117 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2021-41117 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2021-41117? Upgrade keypair to 1.0.4 or later.