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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

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.

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 32th 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.

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

Not in CISA KEV

GHSA-9m9c-vpv5-9g85 — @feathersjs/authenticatio…

Fix: feathersjs/feathers@ee19a0a

GHSA-9m9c-vpv5-9g85 is a security vulnerability in @feathersjs/authentication-oauth. A fix is available for @feathersjs/authentication-oauth — see the affected versions and patch details below.

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

Exploitation data as of Sep 26, 2026 · OSV.dev, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-9m9c-vpv5-9g85.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs32th percentile — riskier than 32% of all scored CVEsHighest risk

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

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

51other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@feathersjs/authentication-oauthnpm

24Kdownloads / 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`npm install @feathersjs/authentication-oauth@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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.

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

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