GHSA-cvw4-c69g-7v7m
NONEInclusion of Untrusted polyfill.io Code Vulnerability in fides.js
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
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 | 2.39.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ethyca-fides. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update ethyca-fides to 2.39.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cvw4-c69g-7v7m 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.
How O3 protects you
O3 pinpoints whether GHSA-cvw4-c69g-7v7m is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-cvw4-c69g-7v7m. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-cvw4-c69g-7v7m in your dependencies?
O3 detects GHSA-cvw4-c69g-7v7m across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.