CVE-2026-27193Network attack vector

Internal header disclosure via readable OAuth session cookie

Published Feb 21, 2026 · Updated Feb 21, 2026

Information exposure in Feathers 5.0.39 and earlier allows remote attackers to read internal HTTP headers from an OAuth session cookie. OAuthService assigns the entire request headers object to session.headers, and cookie-session persists that object as readable base64 data despite signing the cookie. Exposure requires the OAuth flow and a deployment whose reverse proxy or API gateway injects sensitive headers, potentially disclosing API keys, service tokens, and internal IP addresses.

CVSS severity8.2
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information exposure in Feathers 5.0.39 and earlier allows remote attackers to read internal HTTP headers from an OAuth session cookie. OAuthService assigns the entire request headers object to session.headers, and cookie-session persists that object as readable base64 data despite signing the cookie. Exposure requires the OAuth flow and a deployment whose reverse proxy or API gateway injects sensitive headers, potentially disclosing API keys, service tokens, and internal IP addresses.

The record

CVE
CVE-2026-27193
Published
Feb 21, 2026
Updated
Feb 21, 2026
Vendor
FeathersJS
Product
Feathers
Classifications
CWE-200
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 5.0.40

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FeathersJS · Feathersversion=< 5.0.40

Published CVSS scores

8.2GitHub, Inc.CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
5.3NIST NVDCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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