ethyca-fides has a DOM-based XSS vulnerability in fides.js via fides_description override

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.0 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N · score source

EPSS

• CVE-2026-44541: 0.30% estimated exploitation activity in the next 30 days; percentile 22.46 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary fides.js is the script that renders Fides's consent banner on customer websites. It lets the embedding page override the banner's description text at runtime via a URL query parameter, a JavaScript global, or a cookie. On sites that have opted into HTML-formatted descriptions, the overridden value is rendered as live HTML without passing through the server-side sanitiser the rendering path was designed to trust. The result is a DOM-based XSS that any visitor can trigger with a crafted link, no authentication required. The cookie source lets the payload persist, so a single click can plant a payload that fires on every subsequent banner render across all subdomains until cookies are cleared. Am I affected? This vulnerability affects Fides Enterprise deployments that use fides.js for consent management, a.k.a. "Janus", and have HTML-formatted banner descriptions enabled (the FIDESPRIVACYCENTERALLOWHTMLDESCRIPTION Privacy Center container env var set to true ). Deployments that…

Published by the source

14 May 2026, 19:04 UTC

Last modified by the source

13 Jul 2026, 16:43 UTC

Source last checked

26 Oct 2026, 13:45 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-5qrq-9645-g5g2

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-5qrq-9645-g5g2

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# Patch Next advisory brief: CVE-2026-44541

Advisory: ethyca-fides has a DOM-based XSS vulnerability in fides.js via fides_description override
IDs: CVE-2026-44541, GHSA-5qrq-9645-g5g2
Record: https://patchnext.com/advisories/cve-2026-44541 (revision 3, source checked 26 Oct 2026, 13:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: ethyca-fides 2.84.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI ethyca-fides: affected >= 2.33.0, < 2.84.5; fixed in 2.84.5

## Suggested inspection (read-only)
- `python -m pip show ethyca-fides`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on ethyca-fides.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5qrq-9645-g5g2 (OSV record GHSA-5qrq-9645-g5g2 lists affected ranges: PyPI ethyca-fides >=2.33.0 <2.84.5 (fixed))
- Verified: https://github.com/advisories/GHSA-5qrq-9645-g5g2 (GitHub-reviewed advisory GHSA-5qrq-9645-g5g2 lists affected ranges: PyPI ethyca-fides >=2.33.0 <2.84.5)

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