CVE-2024-38537: Fides is an open-source privacy engineering platform. `fides.js`, a client-side script used to interact with the consent management features of Fides,...

Description

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 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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.43%

69.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-829

Affected Software

Vendor	Product	Versions
Ethyca	Fides	< 2.39.1

References

https://fetch.spec.whatwg.orgProduct
https://github.com/ethyca/fides/commit/868c4d629760572192bd61db34f5a4458ed12005Patch
https://github.com/ethyca/fides/pull/5026Issue Tracking, Patch
https://github.com/ethyca/fides/security/advisories/GHSA-cvw4-c69g-7v7mPatch, Third Party Advisory
https://sansec.io/research/polyfill-supply-chain-attackProduct
https://fetch.spec.whatwg.orgProduct
https://github.com/ethyca/fides/commit/868c4d629760572192bd61db34f5a4458ed12005Patch
https://github.com/ethyca/fides/pull/5026Issue Tracking, Patch
https://github.com/ethyca/fides/security/advisories/GHSA-cvw4-c69g-7v7mPatch, Third Party Advisory
https://sansec.io/research/polyfill-supply-chain-attackProduct

Timeline

Published: Jul 2, 2024
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2024-38537?

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 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.

How severe is CVE-2024-38537?

CVE-2024-38537 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.43% probability of exploitation in the next 30 days.

How do I fix CVE-2024-38537?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.