CVE-2024-38537 is a none-severity (CVSS 0) CWE-829 vulnerability in ethyca-fides. A fix is available for ethyca-fides — see the affected versions and patch details below.
Inclusion of Untrusted polyfill.io Code Vulnerability in fides.js
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-38537.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
ethyca-fidesReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | ethyca-fides | all versions | 2.39.1pip install --upgrade 'ethyca-fides==2.39.1' |
Affected Products
fidesethycaDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ethyca-fides, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ethyca-fides to 2.39.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-38537 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2024-38537 in your dependencies?
Find it across PyPI, including transitive dependencies.