Answer in brief
CVE-2024-38537 records a None severity (CVSS 0.0) vulnerability in Inclusion of Untrusted polyfill.io Code Vulnerability in fides.js. The current sources do not mark it as known exploited. The current feed maps ethyca-fides (pypi). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 0.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps ethyca-fides (pypi). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| ethyca-fidespypi | >=0 <2.39.1 | 2.39.1 |
Published upstream
Jul 2, 2024
Evidence: source:osv:source_dates:source-dates:recordSource modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:recordFirst seen by HOL
Sep 10, 2026
### Note 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**. The following sections describe this vulnerability prior to the domain level intervention, when it was still exploitable. ### Impact `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. On June 25th, 2024, Sansec published the following regarding the `polyfill.io` domain. > The polyfill.js is a popular open source library to support older browsers. 100K+ sites embed it using the cdn.polyfill.io domain... However, in February this year, a Chinese company bought the domain and the Github account. Since then, this domain was caught injecting malware on mobile devices via any site that embeds cdn.polyfill.io. 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 compromised domain. No exploitation of `fides.js` via `polyfill.io` has been identified at this time, but other script developers who use `https://cdn.polyfill.io/v2/polyfill.min.js` have reported redirects to malicious websites. ### Patches 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. ### Workarounds 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. caniuse.com/fetch estimates that 97.52% of browser users use a browser that supports the fetch standard. ### References - https://sansec.io/research/polyfill-supply-chain-attack - https://github.com/ethyca/fides/pull/5026/ - https://fetch.spec.whatwg.org/
Quoted source text, attributed separately from HOL analysis.