How severe is GHSA-9m9c-vpv5-9g85?

No CVSS score has been assigned to GHSA-9m9c-vpv5-9g85 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-9m9c-vpv5-9g85?

GHSA-9m9c-vpv5-9g85 affects the following packages: @feathersjs/authentication-oauth (npm). Ecosystems affected: npm.

How do I fix GHSA-9m9c-vpv5-9g85?

Update @feathersjs/authentication-oauth to 5.0.40 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9m9c-vpv5-9g85 is resolved across your whole dependency graph.

How do I detect GHSA-9m9c-vpv5-9g85 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @feathersjs/authentication-oauth. 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-9m9c-vpv5-9g85 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-9m9c-vpv5-9g85?

O3 pinpoints whether GHSA-9m9c-vpv5-9g85 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-9m9c-vpv5-9g85 actively exploited in the wild?

No public exploit code has been indexed for GHSA-9m9c-vpv5-9g85 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-9m9c-vpv5-9g85?

GHSA-9m9c-vpv5-9g85 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 27th 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-9m9c-vpv5-9g85?

GHSA-9m9c-vpv5-9g85 is classified as Information Exposure (CWE-200). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-9m9c-vpv5-9g85 published, and has it been updated?

GHSA-9m9c-vpv5-9g85 was published on February 19, 2026 and was last updated on February 23, 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

GHSA-9m9c-vpv5-9g85

Feathers exposes internal headers via unencrypted session cookie

Also known asCVE-2026-27193

Published

Feb 19, 2026

Updated

Feb 23, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk27th percentile+0.34%

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

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

@feathersjs/authentication-oauthnpm

21Kdownloads / week

Description

All HTTP request headers are stored in the session cookie, which is signed but not encrypted, exposing internal proxy/gateway headers to clients.

The OAuth service stores the complete headers object in the session:

// https://github.com/feathersjs/feathers/blob/dove/packages/authentication-oauth/src/service.ts#L173
session.headers = headers;

The session is persisted using cookie-session, which base64-encodes the data. While the cookie is signed to prevent tampering, the contents are readable by anyone by simply decoding the base64 value.

Under specific deployment configurations (e.g., behind reverse proxies or API gateways), this can lead to exposure of sensitive internal infrastructure details such as API keys, service tokens, and internal IP addresses.

Credits: Abdelwahed Madani Yousfi (@vvxhid) / Edoardo Geraci (@b0-n0-b0) / Thomas Rinsma (@ThomasRinsma) From Codean Labs.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@feathersjs/authentication-oauth`	all versions	5.0.40

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @feathersjs/authentication-oauth. 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 @feathersjs/authentication-oauth to 5.0.40 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9m9c-vpv5-9g85 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-9m9c-vpv5-9g85 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-9m9c-vpv5-9g85. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

All HTTP request headers are stored in the session cookie, which is signed but not encrypted, exposing internal proxy/gateway headers to clients. The OAuth service stores the complete headers object in the session: ```javascript // https://github.com/feathersjs/feathers/blob/dove/packages/authentication-oauth/src/service.ts#L173 session.headers = headers; ``` The session is persisted using `cookie-session`, which base64-encodes the data. While the cookie is signed to prevent tampering, the contents are readable by anyone by simply decoding the base64 value. Under specific deployment configu

O3 Security · Impact-Aware SCA

Is GHSA-9m9c-vpv5-9g85 in your dependencies?

O3 detects GHSA-9m9c-vpv5-9g85 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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