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CVE
CVE-2026-27192
Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. In versions 5.
Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. In versions 5.0.39 and below, origin validation uses startsWith() for comparison, allowing attackers to bypass the check by registering a domain that shares a common prefix with an allowed origin.The getAllowedOrigin() function checks if the Referer header starts with any allowed origin, and this comparison is insufficient as it only validates the prefix. This is exploitable when the origins array is configured and an attacker registers a domain starting with an allowed origin string (e.g., https://target.com.attacker.com bypasses https://target.com).
On its own, tokens are still redirected to a configured origin. However, in specific scenarios an attacker can initiate the OAuth flow from an unauthorized origin and exfiltrate tokens, achieving full account takeover. This issue has bee fixed in version 5.0.40.
HIGH · CVSS 8.1
EPSS 8e-05
Schedule remediation
- CVSS base score ≥ 7.0
Sigma rules0
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-27192, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
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ATT&CK techniques
7Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
T1134 · Access Token Manipulation T1134.001 · Token Impersonation/Theft T1528 · Steal Application Access Token T1539 · Steal Web Session Cookie T1550.004 · Web Session Cookie T1557.002 · ARP Cache Poisoning T1584.002 · DNS Server
▤ Build a SIEM detection for these techniques
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CAPEC attack patterns
12Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.
CAPEC-CAPEC-111 · JSON Hijacking (aka JavaScript Hijacking) CAPEC-CAPEC-141 · Cache Poisoning CAPEC-CAPEC-142 · DNS Cache Poisoning CAPEC-CAPEC-160 · Exploit Script-Based APIs CAPEC-CAPEC-21 · Exploitation of Trusted Identifiers CAPEC-CAPEC-384 · Application API Message Manipulation via Man-in-the-Middle CAPEC-CAPEC-385 · Transaction or Event Tampering via Application API Manipulation CAPEC-CAPEC-386 · Application API Navigation Remapping CAPEC-CAPEC-387 · Navigation Remapping To Propagate Malicious Content CAPEC-CAPEC-388 · Application API Button Hijacking CAPEC-CAPEC-510 · SaaS User Request Forgery CAPEC-CAPEC-59 · Session Credential Falsification through Prediction
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Weakness Classification
CWE-346Origin Validation Error
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Affected Products & Versions
1feathersjs feathers< 5.0.40
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Affected Packages
1Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
npm
@feathersjs/authentication-oauth
HIGH
fixed in 5.0.40
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Scoring & Timeline
8.1
HIGH · CVSS v3.1 · [email protected]
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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References & Sources
3Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/feathersjs/feathers/security/advisories/GHSA-mp4x-c34x-wv3xThird Party Advisory