Cyber Resilience

CVE-2026-27192

Feathersjs Feathers ≤ 5.0.40

Published
21 February 2026
Modified
25 February 2026
Patch / advisory
View advisory
CVSS Score v4 7.6
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0024 15th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-27192 is a high-severity Origin Validation Error (CWE-346) vulnerability in Feathersjs Feathers. Its CVSS base score is 7.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique DHCP Spoofing (T1557.003); ranked at the 15th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and IA-3 (Device Identification and Authentication) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-27192 affects Feathersjs, a framework for building web APIs and real-time applications using TypeScript or JavaScript, specifically in versions 5.0.39 and earlier. The vulnerability stems from improper origin validation in the getAllowedOrigin() function, which uses the startsWith() method to compare the Referer header against a list of allowed origins. This prefix-based check is insufficient, as it permits bypasses when an attacker registers a domain that shares a common prefix with an allowed origin, such as https://target.com.attacker.com evading validation for https://target.com. The issue is tied to CWE-346 (Origin Validation Error) and carries a CVSS v3.1 base score of 8.1 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).

Any remote attacker without privileges can exploit this when the origins array is configured in the application. By controlling a malicious domain with a prefix-matching origin, the attacker can trick the validation into allowing requests from unauthorized sources. While tokens are typically redirected to a configured origin, attackers can initiate an OAuth flow from the malicious origin, exfiltrate authentication tokens, and achieve full account takeover in specific scenarios.

The vulnerability has been fixed in Feathersjs version 5.0.40, as detailed in the project's security advisory (GHSA-mp4x-c34x-wv3x), release notes, and the patching commit (ee19a0ae9bc2ebf23b1fe598a1f7361981b65401). Security practitioners should upgrade to version 5.0.40 or later and review configurations involving origin validation and OAuth flows.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-346

Related Threats

MITRE ATT&CK Enterprise Techniques

T1557.003 DHCP Spoofing Credential Access
Adversaries may redirect network traffic to adversary-owned systems by spoofing Dynamic Host Configuration Protocol (DHCP) traffic and acting as a malicious DHCP server on the victim network.
attack.mitre.org →
T1557 Adversary-in-the-Middle Credential Access
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as [Network Sniffing](https://attack.
attack.mitre.org →
T1557.001 Name Resolution Poisoning and SMB Relay Credential Access
By responding to LLMNR/NBT-NS/mDNS network traffic, adversaries may spoof an authoritative source for name resolution to force communication with an adversary controlled system.
attack.mitre.org →
T1557.002 ARP Cache Poisoning Credential Access
Adversaries may poison Address Resolution Protocol (ARP) caches to position themselves between the communication of two or more networked devices.
attack.mitre.org →
T1557.004 Evil Twin Credential Access
Adversaries may host seemingly genuine Wi-Fi access points to deceive users into connecting to malicious networks as a way of supporting follow-on behaviors such as [Network Sniffing](https://attack.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-29792Same product: Feathersjs Feathers
CVE-2026-29793Same product: Feathersjs Feathers
CVE-2026-27193Same product: Feathersjs Feathers
CVE-2026-27191Same product: Feathersjs Feathers
CVE-2023-37899Same product: Feathersjs Feathers
CVE-2026-56181Shared CWE-346
CVE-2026-66298Shared CWE-346
CVE-2023-28164Shared CWE-346
CVE-2026-11226Shared CWE-346
CVE-2026-23552Shared CWE-346

Affected Assets

feathersjs
feathers
≤ 5.0.40

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

AC-4 Information Flow Enforcement good match

Information flow enforcement directly requires validating the source of data before allowing transmission or receipt.

IA-3 Device Identification and Authentication good match

Device identification and authentication mandates verifying the source before establishing connections.

SC-23 Session Authenticity good match

Session authenticity mechanisms require validation that communications originate from the expected party.

SC-7 Boundary Protection partial match

Boundary protection at interfaces enforces checks on the origin of incoming communications.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 mostly match
prevents

Authentication directly verifies the source of users/services/hardware, mitigating origin validation failures.

PR.AA-04 mostly match
prevents

Verifying identity assertions enforces origin validation for conveyed claims.

ID.AM-03 partial match
prevents

Documenting authorized flows supports origin validation by defining expected sources.

PR.IR-01 partial match
prevents

Protecting networks from unauthorized access requires origin checks on communication sources.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.20 Networks security partial match
mitigates

Network security controls enforce origin validation at network boundaries.

A.8.21 Security of network services partial match
mitigates

Security of network services includes validating the authenticity of service endpoints.

A.8.22 Segregation of networks partial match
mitigates

Network segregation reduces exposure but does not directly validate origins.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for origin validation of inputs and communications.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles encourage origin checks but do not mandate them.

A.8.28 Secure coding partial match
prevents

Secure coding practices include implementing proper origin validation to prevent spoofing.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (3 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-346
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-346
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-346

References