How severe is GHSA-c3m8-x3cg-qm2c?

GHSA-c3m8-x3cg-qm2c 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 GHSA-c3m8-x3cg-qm2c?

GHSA-c3m8-x3cg-qm2c affects the following packages: helmet-csp (npm). Ecosystems affected: npm.

How do I fix GHSA-c3m8-x3cg-qm2c?

Update helmet-csp to 2.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c3m8-x3cg-qm2c is resolved across your whole dependency graph.

How do I detect GHSA-c3m8-x3cg-qm2c in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for helmet-csp. 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-c3m8-x3cg-qm2c 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-c3m8-x3cg-qm2c?

O3 pinpoints whether GHSA-c3m8-x3cg-qm2c 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-c3m8-x3cg-qm2c actively exploited in the wild?

No public exploit code has been indexed for GHSA-c3m8-x3cg-qm2c 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-c3m8-x3cg-qm2c published, and has it been updated?

GHSA-c3m8-x3cg-qm2c was published on September 3, 2020 and was last updated on September 29, 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

MEDIUM severity

GHSA-c3m8-x3cg-qm2c

MEDIUMFix: helmetjs/csp@67a69ba

GHSA-c3m8-x3cg-qm2c is a medium-severity (CVSS 6.5) vulnerability in helmet-csp. O3 Security confirms whether GHSA-c3m8-x3cg-qm2c is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Configuration Override in helmet-csp

Published

Sep 3, 2020

Updated

Sep 29, 2021

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 29, 2021 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

📦helmet-csp

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

Description

Versions of helmet-csp before to 2.9.1 are vulnerable to a Configuration Override affecting the application's Content Security Policy (CSP). The package's browser sniffing for Firefox deletes the default-src CSP policy, which is the fallback policy. This allows an attacker to remove an application's default CSP, possibly rendering the application vulnerable to Cross-Site Scripting.

Recommendation

Upgrade to version 2.9.1 or later. Setting the browserSniff configuration to false in vulnerable versions also mitigates the issue.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`helmet-csp`	≥ 1.2.2&&< 2.9.1	2.9.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for helmet-csp. 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 helmet-csp to 2.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c3m8-x3cg-qm2c 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-c3m8-x3cg-qm2c 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-c3m8-x3cg-qm2c. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Versions of `helmet-csp` before to 2.9.1 are vulnerable to a Configuration Override affecting the application's Content Security Policy (CSP). The package's browser sniffing for Firefox deletes the `default-src` CSP policy, which is the fallback policy. This allows an attacker to remove an application's default CSP, possibly rendering the application vulnerable to Cross-Site Scripting. ## Recommendation Upgrade to version 2.9.1 or later. Setting the `browserSniff` configuration to `false` in vulnerable versions also mitigates the issue.

O3 Security · Impact-Aware SCA

Is GHSA-c3m8-x3cg-qm2c in your dependencies?

O3 detects GHSA-c3m8-x3cg-qm2c 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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