CVE-2026-27193
MEDIUM
GHSA-9m9c-vpv5-9g85
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Lifecycle Timeline
3Description
Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. In versions 5.0.39 and below, 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, then 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. This issue has been fixed in version 5.0.40.
Analysis
Feathersjs versions 5.0.39 and below store unencrypted HTTP headers in base64-encoded session cookies, allowing attackers with network access to decode and retrieve sensitive internal infrastructure details such as API keys, service tokens, and internal IP addresses. Authenticated users can exploit this vulnerability in deployments behind reverse proxies or API gateways to gain unauthorized access to sensitive information. …
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Remediation
Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Review data exposure and access controls.
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External POC / Exploit Code
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