How severe is CVE-2021-41090?

CVE-2021-41090 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-41090?

CVE-2021-41090 affects the following packages: github.com/grafana/agent (Go). Ecosystems affected: Go.

How do I fix CVE-2021-41090?

Update github.com/grafana/agent to 0.21.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41090 is resolved across your whole dependency graph.

How do I detect CVE-2021-41090 in my Go dependencies?

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

How do I mitigate CVE-2021-41090 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-2021-41090 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-41090 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-2021-41090?

CVE-2021-41090 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 54th 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-2021-41090?

CVE-2021-41090 is classified as Information Exposure (CWE-200), CWE-312 (CWE-312). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-41090 published, and has it been updated?

CVE-2021-41090 was published on December 8, 2021 and was last updated on August 27, 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

Not in CISA KEV

HIGH severity

CVE-2021-41090 — agent

HIGHFix: grafana/agent@af7fb01

CVE-2021-41090 is a high-severity (CVSS 7.5) Information Exposure vulnerability in github.com/grafana/agent. A fix is available for github.com/grafana/agent — see the affected versions and patch details below.

Instance config inline secret exposure in Grafana

Also known asGHSA-9c4x-5hgq-q3whGO-2022-0305

Published

Dec 8, 2021

Updated

Aug 27, 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 ↗

0.8%probability of exploitation in next 30 days

Lower Risk+0.02%

Lower risk than most CVEs54th percentile — riskier than 54% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2021-41090 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 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

🐹github.com/grafana/agent

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

Impact

Some inline secrets are exposed in plaintext over the Grafana Agent HTTP server:

Inline secrets for metrics instance configs in the base YAML file are exposed at /-/config
Inline secrets for integrations are exposed at /-/config
Inline secrets for Consul ACL tokens and ETCD basic auth when configured for the scraping service at /-/config.
Inline secrets for the Kafka receiver for OpenTelemetry-Collector tracing at /-/config.
Inline secrets for metrics instance configs loaded from the scraping service are exposed at /agent/api/v1/configs/{name}.

Inline secrets will be exposed to anyone being able to reach these endpoints.

Secrets found in these sections are used for:

Delivering metrics to a Prometheus Remote Write system
Authenticating against a system for discovering Prometheus targets
Authenticating against a system for collecting metrics (scrape_configs and integrations)
Authenticating against a Consul or ETCD for storing configurations to distribute in scraping service mode
Authenticating against Kafka for receiving traces

Non-inlined secrets, such as *_file-based secrets, are not impacted by this vulnerability.

Patches

Download v0.20.1 or any version past v0.21.2 to patch Grafana Agent. These patches obfuscate the listed impacted secrets from the vulnerable endpoints.

The patches also disable the endpoints by default. Pass the command-line flag --config.enable-read-api to opt-in and re-enable the endpoints.

Workarounds

If for some reason you cannot upgrade, use non-inline secrets where possible. Not all configuration options may have a non-inline equivalent.

You also may desire to restrict API access to Grafana Agent, with some combination of:

Restrict network interfaces Grafana Agent listens on through http_listen_address in the server block. 127.0.0.1 is the most restrictive, 0.0.0.0 is the default.
Configure Grafana Agent to use HTTPS with client authentication.
Use firewall rules to restrict external access to Grafana Agent's API.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/grafana/agent`	≥ 0.14.0&&< 0.21.2	0.21.2`go get github.com/grafana/agent@v0.21.2`

Affected Products

1 product · 2 configurations

Application

agentgrafana

≥ 0.21.0 && < 0.21.2

range

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/grafana/agent, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/grafana/agent to 0.21.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41090 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 Some inline secrets are exposed in plaintext over the Grafana Agent HTTP server: * Inline secrets for metrics instance configs in the base YAML file are exposed at `/-/config` * Inline secrets for integrations are exposed at `/-/config` * Inline secrets for Consul ACL tokens and ETCD basic auth when configured for the scraping service at `/-/config`. * Inline secrets for the Kafka receiver for OpenTelemetry-Collector tracing at `/-/config`. * Inline secrets for metrics instance configs loaded from the scraping service are exposed at `/agent/api/v1/configs/{name}`. Inline secrets