CVE-2024-38537
Inclusion of Untrusted polyfill.io Code Vulnerability in fides.js
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Inclusion of Untrusted polyfill.io Code Vulnerability in fides.js
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.
- Record
CVE-2024-38537- CVSS 3.1
- 0.0 None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N - Weakness
- CWE-829
- Updated
- 2026-11-02
EUVDEUVD-2024-2328
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.
- Record
EUVD-2024-2328- CVSS 3.1
- 0.0 None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-cvw4-c69g-7v7m
Inclusion of Untrusted polyfill.io Code Vulnerability in fides.js
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
- Record
GHSA-cvw4-c69g-7v7m- CVSS 3.1
- 0.0 None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N - Weakness
- CWE-829
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2024-38537- CVSS 3.1
- 0.0 None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-829
- Updated
- 2026-11-02
OSV
Inclusion of Untrusted polyfill.io Code Vulnerability in fides.js
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.
- Record
CVE-2024-38537- CVSS 3.1
- 0.0 None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N - Weakness
- CWE-829
- Updated
- 2026-11-02
OSVGHSA-cvw4-c69g-7v7m
Inclusion of Untrusted polyfill.io Code Vulnerability in fides.js
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
- Record
GHSA-cvw4-c69g-7v7m- CVSS 3.1
- 0.0 None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N - Weakness
- CWE-829
- Updated
- 2026-11-02
OSVPYSEC-2026-1339
Inclusion of Untrusted polyfill.io Code Vulnerability in fides.js
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
- Record
PYSEC-2026-1339- CVSS 3.1
- 0.0 None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ethyca-fidesPyPI |
before 2.39.1 | 2.39.1 |
ethyca-fidesPyPI |
before 2.39.1, plus listed versions 1.9.92.0.02.1.02.10.02.11.0 Show 45 moreShow less2.12.02.12.12.13.02.14.02.14.12.14.22.15.02.15.12.16.02.17.02.17.12.18.02.19.02.19.12.2.02.2.12.2.22.20.02.20.12.20.22.21.02.22.02.22.12.23.02.23.12.23.22.23.32.24.02.24.12.25.02.26.02.26.32.27.02.28.02.29.02.3.02.3.12.30.02.30.12.31.02.32.02.33.02.33.12.34.02.35.0 |
2.39.1 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | Havoc10-sw/Detect_polyfill_CVE-2024-38537- | 2024-07-07 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-38537 is a none vulnerability (CVSS 0.0) in Ethyca Fides, published July 2, 2024. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 1.43%, the 73rd percentile. Fixed in ethyca-fides 2.39.1.
References
Left out here: 25 versions. The JSON record has them.