What is GHSA-2c64-vj8g-vwrq?

(This advisory is canonically https://advisories.nats.io/CVE/CVE-2020-26892.txt ) ## Problem Description NATS nats-server through 2020-10-07 has Incorrect Access Control because of how expired credentials are handled. The NATS accounts system has expiration timestamps on credentials; the library had an API which encouraged misuse and an `IsRevoked()` method which misused its own API. A new `IsClaimRevoked()` method has correct handling and the nats-server has been updated to use this. The old `IsRevoked()` method now always returns true and other client co

How severe is GHSA-2c64-vj8g-vwrq?

No CVSS score has been assigned to GHSA-2c64-vj8g-vwrq yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-2c64-vj8g-vwrq?

GHSA-2c64-vj8g-vwrq affects the following packages: github.com/nats-io/nats-server/v2 (Go). Ecosystems affected: Go.

How do I fix GHSA-2c64-vj8g-vwrq?

Update github.com/nats-io/nats-server/v2 to 2.1.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2c64-vj8g-vwrq is resolved across your whole dependency graph.

How do I detect GHSA-2c64-vj8g-vwrq in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/nats-io/nats-server/v2. 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-2c64-vj8g-vwrq 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-2c64-vj8g-vwrq?

O3 pinpoints whether GHSA-2c64-vj8g-vwrq 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-2c64-vj8g-vwrq actively exploited in the wild?

No public exploit code has been indexed for GHSA-2c64-vj8g-vwrq 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 GHSA-2c64-vj8g-vwrq?

GHSA-2c64-vj8g-vwrq has an EPSS (Exploit Prediction Scoring System) score of 2.1%, placing it in the 79th 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 GHSA-2c64-vj8g-vwrq?

GHSA-2c64-vj8g-vwrq is classified as Hard-coded Credentials (CWE-798). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-2c64-vj8g-vwrq published, and has it been updated?

GHSA-2c64-vj8g-vwrq was published on May 21, 2021 and was last updated on February 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

GHSA-2c64-vj8g-vwrq

Incorrect handling of credential expiry by /nats-io/nats-server

Also known asCVE-2020-26892 GHSA-4w5x-x539-ppf5GO-2022-0380

Published

May 21, 2021

Updated

Feb 4, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

2.1%probability of exploitation in next 30 days

Lower Risk79th percentile+1.50%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐹github.com/nats-io/nats-server/v2

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

(This advisory is canonically https://advisories.nats.io/CVE/CVE-2020-26892.txt )

Problem Description

NATS nats-server through 2020-10-07 has Incorrect Access Control because of how expired credentials are handled.

The NATS accounts system has expiration timestamps on credentials; the https://github.com/nats-io/jwt library had an API which encouraged misuse and an IsRevoked() method which misused its own API.

A new IsClaimRevoked() method has correct handling and the nats-server has been updated to use this. The old IsRevoked() method now always returns true and other client code will have to be updated to avoid calling it.

The CVE identifier should cover any application using the old JWT API, where the nats-server is one of those applications.

Affected versions

JWT library

all versions prior to 1.1.0
fixed after nats-io/jwt PR 103 landed (2020-10-06)

NATS Server

Version 2 prior to 2.1.9
- 2.0.0 through and including 2.1.8 are vulnerable.
fixed with nats-io/nats-server PRs 1632, 1635, 1645

Impact

Time-based credential expiry did not work.

Workaround

Have credentials which only expire after fixes can be deployed.

Solution

Upgrade the JWT dependency in any application using it.

Upgrade the NATS server if using NATS Accounts.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/nats-io/nats-server/v2`	all versions	2.1.9

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/nats-io/nats-server/v2. 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 github.com/nats-io/nats-server/v2 to 2.1.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2c64-vj8g-vwrq 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-2c64-vj8g-vwrq 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-2c64-vj8g-vwrq. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

(This advisory is canonically https://advisories.nats.io/CVE/CVE-2020-26892.txt ) ## Problem Description NATS nats-server through 2020-10-07 has Incorrect Access Control because of how expired credentials are handled. The NATS accounts system has expiration timestamps on credentials; the <https://github.com/nats-io/jwt> library had an API which encouraged misuse and an `IsRevoked()` method which misused its own API. A new `IsClaimRevoked()` method has correct handling and the nats-server has been updated to use this. The old `IsRevoked()` method now always returns true and other client co

O3 Security · Impact-Aware SCA

Is GHSA-2c64-vj8g-vwrq in your dependencies?

O3 detects GHSA-2c64-vj8g-vwrq across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works