Rails HTML Sanitizers: Possible XSS vulnerability with certain configurations

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-73648: 0.55% estimated exploitation activity in the next 30 days; percentile 45.91 (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 There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors. - Versions affected: = 1.0.3, < 1.7.1 - Not affected: < 1.0.3 - Fixed versions: 1.7.1 Impact Rails::HTML::PermitScrubber restricts SVG reference elements in the SVGALLOWLOCALHREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage can load external images, which can be used for tracking. Applications are impacted…

Published by the source

21 Jul 2026, 22:05 UTC

Last modified by the source

13 Aug 2026, 18:00 UTC

Source last checked

26 Oct 2026, 15:52 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-cj75-f6xr-r4g7

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# Patch Next advisory brief: CVE-2026-73648

Advisory: Rails HTML Sanitizers: Possible XSS vulnerability with certain configurations
IDs: CVE-2026-73648, GHSA-cj75-f6xr-r4g7
Record: https://patchnext.com/advisories/cve-2026-73648 (revision 1, source checked 26 Oct 2026, 15:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: rails-html-sanitizer 1.7.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems rails-html-sanitizer: affected >= 1.0.3, < 1.7.1; fixed in 1.7.1

## Suggested inspection (read-only)
- RubyGems rails-html-sanitizer: check the installed version with your package manager.

## 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 rails-html-sanitizer.
- 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://github.com/advisories/GHSA-cj75-f6xr-r4g7 (GitHub-reviewed advisory GHSA-cj75-f6xr-r4g7 lists affected ranges: RubyGems rails-html-sanitizer >=1.0.3 <1.7.1)

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