How severe is CVE-2021-21421?

CVE-2021-21421 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-21421?

CVE-2021-21421 affects the following packages: node-etsy-client (npm). Ecosystems affected: npm.

How do I fix CVE-2021-21421?

Update node-etsy-client to 0.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21421 is resolved across your whole dependency graph.

How do I detect CVE-2021-21421 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for node-etsy-client, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-21421 if there is no patch (or I can't update yet)?

Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Is CVE-2021-21421 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-21421 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-21421?

CVE-2021-21421 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 64th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-21421?

CVE-2021-21421 is classified as Information Exposure (CWE-200), CWE-209 (CWE-209). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-21421 published, and has it been updated?

CVE-2021-21421 was published on April 1, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

CVE-2021-21421 — node-etsy-client

MEDIUMFix: creharmony/node-etsy-client@b4beb8e

CVE-2021-21421 is a medium-severity (CVSS 6.5) Information Exposure vulnerability in node-etsy-client. A fix is available for node-etsy-client — see the affected versions and patch details below.

ApiKey secret could be revelated on network issue

Also known asGHSA-xw22-wv29-3299

Published

Apr 1, 2021

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs64th percentile — riskier than 64% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-21421 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

node-etsy-clientnpm

118downloads / week

Description

Impact

What kind of vulnerability is it? Who is impacted? Applications that are using node-etsy-client and reporting client error to the end user will offer api key value too

Patches

Has the problem been patched? What versions should users upgrade to?

creharmony/node-etsy-client#18 fixes this issue. This is fixed in node-etsy-client v0.3.0 and later.

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

Do not report or log etsy client error if you are using version <= v0.2.0

Update your version of node-etsy-client

References

Are there any links users can visit to find out more?

https://github.com/creharmony/node-etsy-client/issues/17 : On connect error secret appears in error #17

For more information

If you have any questions or comments about this advisory:

Open an issue in github.com/creharmony/node-etsy-client/issues

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`node-etsy-client`	all versions	0.3.0`npm install node-etsy-client@0.3.0`

Affected Products

1 product · 1 configurations

Application

node-etsy-clientnode-etsy-client_project

≤ 0.3.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for node-etsy-client, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update node-etsy-client to 0.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21421 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Frequently Asked Questions

### Impact _What kind of vulnerability is it? Who is impacted?_ Applications that are using node-etsy-client and reporting client error to the end user will offer api key value too ### Patches _Has the problem been patched? What versions should users upgrade to?_ creharmony/node-etsy-client#18 fixes this issue. This is fixed in [node-etsy-client v0.3.0](https://github.com/creharmony/node-etsy-client/tree/v0.3.0) and later. ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ Do not report or log etsy client error if you are using version <= v0