Cyber Resilience

CVE-2024-38537

Ethyca Fides ≤ 2.39.1

Published
02 July 2024
Modified
02 September 2025
Patch / advisory
View advisory
CVSS Score v3.1 0.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N
EPSS Score 0.014 71th percentile
Risk Priority 45 floored blend · peak EPSS

Summary

CVE-2024-38537 is a uncategorised-severity Inclusion of Functionality from Untrusted Control Sphere (CWE-829) vulnerability in Ethyca Fides. Its CVSS base score is 0.0.

Operationally, exploitation aligns with the MITRE ATT&CK technique Supply Chain Compromise (T1195); ranked in the top 29% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SR-4 (Provenance) and SR-11 (Component Authenticity) — 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.

Fides is an open-source privacy engineering platform whose client-side consent script fides.js contained a dependency on the polyfill.io domain. The script loaded resources from that domain only in a narrow edge case when a legacy browser such as IE11 lacking native fetch support was detected, introducing an inclusion of functionality from an untrusted control sphere (CWE-829).

An attacker who had already compromised polyfill.io could therefore serve malicious JavaScript to any visitor using one of those pre-2017 browsers on a page that included fides.js, resulting in arbitrary code execution within the victim’s browser context. No evidence of such exploitation against fides.js has been observed.

The issue was corrected in Fides 2.39.1. On 27 June 2024 Cloudflare and Namecheap blocked resolution of polyfill.io and its subdomains, eliminating the attack surface for all clients regardless of browser version. Prior to that intervention the only reliable client-side mitigation was use of a modern browser that implements the fetch standard.

The associated EPSS score reached a peak of 0.2223 with no subsequent material increase.

OWASP Top 10 for Web (2025)

A08:2025 Software or Data Integrity Failures

EU & UK References

Vulnerability Data

Fides is an open-source privacy engineering platform. `fides.js`, a client-side script used to interact with the consent management features of Fides, used the `polyfill.io` domain in a very limited edge case, when it detected a legacy browser such as IE11…

more

that did not support the fetch standard. Therefore it was possible for users of legacy, pre-2017 browsers who navigate to a page serving `fides.js` to download and execute malicious scripts from the `polyfill.io` domain when the domain was compromised and serving malware. No exploitation of `fides.js` via `polyfill.io` has been identified as of time of publication. The vulnerability has been patched in Fides version `2.39.1`. Users are advised to upgrade to this version or later to secure their systems against this threat. On Thursday, June 27, 2024, Cloudflare and Namecheap intervened at a domain level to ensure `polyfill.io` and its subdomains could not resolve to the compromised service, rendering this vulnerability unexploitable. Prior to the domain level intervention, there were no server-side workarounds and the confidentiality, integrity, and availability impacts of this vulnerability were high. Clients could ensure they were not affected by using a modern browser that supported the fetch standard.

CWE(s)
CWE-829

Related Threats

MITRE ATT&CK Enterprise Techniques

T1195 Supply Chain Compromise Initial Access
Adversaries may manipulate products or product delivery mechanisms prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
T1176 Software Extensions Persistence
Adversaries may abuse software extensions to establish persistent access to victim systems.
attack.mitre.org →
T1195.001 Compromise Software Dependencies and Development Tools Initial Access
Adversaries may manipulate software dependencies and development tools prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
T1505.004 IIS Components Persistence
Adversaries may install malicious components that run on Internet Information Services (IIS) web servers to establish persistence.
attack.mitre.org →
T1505.005 Terminal Services DLL Persistence
Adversaries may abuse components of Terminal Services to enable persistent access to systems.
attack.mitre.org →
T1574.006 Dynamic Linker Hijacking Stealth
Adversaries may execute their own malicious payloads by hijacking environment variables the dynamic linker uses to load shared libraries.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-47114Same product: Ethyca Fides
CVE-2025-57815Same product: Ethyca Fides
CVE-2023-46125Same product: Ethyca Fides
CVE-2024-31223Same product: Ethyca Fides
CVE-2025-57816Same product: Ethyca Fides
CVE-2023-37480Same product: Ethyca Fides
CVE-2023-48224Same product: Ethyca Fides
CVE-2024-52008Same product: Ethyca Fides
CVE-2023-46124Same product: Ethyca Fides
CVE-2024-45053Same product: Ethyca Fides

Affected Assets

ethyca
fides
≤ 2.39.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 6 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V14.2.3
  • V3.5.6
  • V9.1.3
  • V15.3.2

Mitigating Controls (NIST 800-53 r5) AI

SR-4 Provenance good match

Requires documented, valid provenance for components, preventing acceptance of code from outside the trusted sphere.

SR-11 Component Authenticity partial match

Implements detection and prevention of counterfeit or inauthentic components before they are integrated.

SR-3 Supply Chain Controls and Processes partial match

Establishes processes to identify and address supply-chain weaknesses that would allow untrusted functionality.

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.

ID.RA-09 full match
prevents

Pre-acquisition integrity/authenticity checks directly prevent inclusion of untrusted code.

GV.SC-01 mostly match
prevents

Supply-chain program directly governs inclusion of third-party executable code.

GV.SC-05 mostly match
prevents

Contractual requirements can mandate trusted sources and integrity checks for included functionality.

GV.SC-07 mostly match
prevents

Supplier risk assessment explicitly covers risks from their products and libraries.

ID.RA-10 mostly match
prevents

Critical-supplier assessment reduces risk of importing executable functionality from untrusted parties.

PR.PS-06 mostly match
prevents

Secure SDLC practices include dependency vetting and trusted-source policies.

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.5.21 Managing information security in the ICT supply chain mostly match
prevents

By requiring suppliers to propagate security requirements and to disclose component provenance, the control limits the inclusion of functionality obtained from untrusted third-party sources without oversight.

A.8.23 Web filtering none match
none

Blocking domains that serve malware or untrusted scripts prevents the browser from automatically including functionality from an attacker-controlled source.

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 (1 rule)
  • V-248635 Executable search paths within the initialization files of all local interactive OL 8 users must only contain paths that resolve to the system default or the user's home directory. prevents CWE-829
Oracle Linux 9 (1 rule)
  • V-271847 OL 9 must be configured so that executable search paths within the initialization files of all local interactive users must only contain paths that resolve to the system default or the users home directory. prevents CWE-829
RHEL 7 (1 rule)
  • V-204477 The Red Hat Enterprise Linux operating system must be configured so that all local interactive user initialization files executable search paths contain only paths that resolve to the users home directory. prevents CWE-829
RHEL 8 (1 rule)
  • V-230317 Executable search paths within the initialization files of all local interactive RHEL 8 users must only contain paths that resolve to the system default or the users home directory. prevents CWE-829
RHEL 9 (1 rule)
  • V-258050 Executable search paths within the initialization files of all local interactive RHEL 9 users must only contain paths that resolve to the system default or the users home directory. prevents CWE-829
Windows 10 (1 rule)
  • V-220737 Administrative accounts must not be used with applications that access the Internet, such as web browsers, or with potential Internet sources, such as email. prevents CWE-829

References