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VulnerabilityPublished Updated

CVE-2026-27193: feathersjs feathers · Information Exposure

Affects feathersjs feathersSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High : upgrade to 5.0.40 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.0.40
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 21 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade feathersjs feathers to 5.0.40.

Affected software

ProductAffectedFixed in
feathersjsfeathersAffected
  • <5.0.40
Fixed in
  • 5.0.40

AI-suggested

To mitigate this vulnerability, organizations should immediately upgrade feathersjs to version 5.0.40 or later, where the issue is fixed. Additionally, review and harden deployment configurations to ensure that internal headers are not unnecessarily forwarded to application layers or included in session data. Implement encryption for session cookies rather than relying solely on signing to prevent unauthorized reading of cookie contents. Audit OAuth and session management implementations to avoid storing sensitive headers or tokens in client-accessible storage. Employ network segmentation and strict access controls to limit exposure of internal IP addresses and service tokens. Monitoring and alerting on unusual access patterns or session anomalies can help detect exploitation attempts. Finally, conduct thorough security testing and code reviews for custom middleware that interacts with headers and sessions to prevent similar issues.

Description

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.

References

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