How severe is GHSA-prmc-5v5w-c465?

No CVSS score has been assigned to GHSA-prmc-5v5w-c465 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-prmc-5v5w-c465?

GHSA-prmc-5v5w-c465 affects the following packages: nats (npm). Ecosystems affected: npm.

How do I fix GHSA-prmc-5v5w-c465?

Update nats to 2.0.0-209 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-prmc-5v5w-c465 is resolved across your whole dependency graph.

How do I detect GHSA-prmc-5v5w-c465 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nats. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-prmc-5v5w-c465 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-prmc-5v5w-c465?

O3 pinpoints whether GHSA-prmc-5v5w-c465 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-prmc-5v5w-c465 actively exploited in the wild?

No public exploit code has been indexed for GHSA-prmc-5v5w-c465 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.

When was GHSA-prmc-5v5w-c465 published, and has it been updated?

GHSA-prmc-5v5w-c465 was published on April 6, 2021 and was last updated on March 31, 2021. 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

GHSA-prmc-5v5w-c465

GHSA-prmc-5v5w-c465 is a security vulnerability in nats. O3 Security confirms whether GHSA-prmc-5v5w-c465 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Client TLS credentials sent raw to server in npm package nats

Published

Apr 6, 2021

Updated

Mar 31, 2021

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Mar 31, 2021 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.

natsnpm

953Kdownloads / week

Description

Nats is a Node.js client for the NATS messaging system.

Problem Description

Preview versions of two NPM packages and one Deno package from the NATS project contain an information disclosure flaw, leaking options to the NATS server; for one package, this includes TLS private credentials.

The connection configuration options in these JavaScript-based implementations were fully serialized and sent to the server in the client's CONNECT message, immediately after TLS establishment.

The nats.js client supports Mutual TLS and the credentials for the TLS client key are included in the connection configuration options; disclosure of the client's TLS private key to the server has been observed.

Most authentication mechanisms are handled after connection, instead of as part of connection, so other authentication mechanisms are unaffected. For clarity: NATS account NKey authentication is NOT affected.

Neither the nats.ws nor the nats.deno clients support Mutual TLS: the affected versions listed below are those where the logic flaw is present. We are including the nats.ws and nats.deno versions out of an abundance of caution, as library maintainers, but rate as minimal the likelihood of applications leaking sensitive data.

Affected versions

Security impact

NPM package nats.js:
- mainline is unaffected
- beta branch is vulnerable from 2.0.0-201, fixed in 2.0.0-209

Logic flaw

NPM package nats.ws:
- status: preview
- flawed from 1.0.0-85, fixed in 1.0.0-111
Deno repository https://github.com/nats-io/nats.deno
- status: preview
- flawed in all git tags prior to fix
- fixed with git tag v1.0.0-9

Impact

For deployments using TLS client certificates (for mutual TLS), private key material for TLS is leaked from the client application to the server. If the server is untrusted (run by a third party), or if the client application also disables TLS verification (and so the true identity of the server is unverifiable) then authentication credentials are leaked.

Workaround

None

Solution

Upgrade your package dependencies to fixed versions, and then reissue any TLS client credentials (with new keys, not just new certificates) and revoke the old ones.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`nats`	≥ 2.0.0-201&&< 2.0.0-209	2.0.0-209

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nats. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update nats to 2.0.0-209 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-prmc-5v5w-c465 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-prmc-5v5w-c465 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-prmc-5v5w-c465. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Nats is a Node.js client for the NATS messaging system. ## Problem Description _Preview versions_ of two NPM packages and one Deno package from the NATS project contain an information disclosure flaw, leaking options to the NATS server; for one package, this includes TLS private credentials. The _connection_ configuration options in these JavaScript-based implementations were fully serialized and sent to the server in the client's `CONNECT` message, immediately after TLS establishment. The nats.js client supports Mutual TLS and the credentials for the TLS client key are included in the con

O3 Security · Impact-Aware SCA

Is GHSA-prmc-5v5w-c465 in your dependencies?

O3 detects GHSA-prmc-5v5w-c465 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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