How severe is CVE-2026-73648?

No CVSS score has been assigned to CVE-2026-73648 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-73648?

CVE-2026-73648 affects the following packages: rails-html-sanitizer (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2026-73648?

Update rails-html-sanitizer to 1.7.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-73648 is resolved across your whole dependency graph.

How do I detect CVE-2026-73648 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rails-html-sanitizer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-73648 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-73648 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-73648 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-73648?

CVE-2026-73648 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 44th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-73648?

CVE-2026-73648 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-73648 published, and has it been updated?

CVE-2026-73648 was published on August 13, 2026 and was last updated on October 5, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎 RubyGems

Not in CISA KEV

CVE-2026-73648 — rails-html-sanitizer

Fix: rails/rails-html-sanitizer@74dcb80

CVE-2026-73648 is a Cross-site Scripting (XSS) vulnerability in rails-html-sanitizer. A fix is available for rails-html-sanitizer — see the affected versions and patch details below.

rails-html-sanitizer: Possible XSS vulnerability with certain configurations

Also known asGHSA-cj75-f6xr-r4g7

Published

Aug 13, 2026

Updated

Oct 5, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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-2026-73648.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs44th percentile — riskier than 44% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

💎rails-html-sanitizer

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

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 SVG_ALLOW_LOCAL_HREF 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 only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

Credit

Found by maintainer Mike Dalessio during a security audit.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`rails-html-sanitizer`	≥ 1.0.3&&< 1.7.1	1.7.1`bundle update rails-html-sanitizer --conservative`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rails-html-sanitizer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rails-html-sanitizer to 1.7.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-73648 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

rails-html-sanitizer sanitizes HTML fragments in Rails applications. This issue is a cross-site scripting vulnerability affecting versions 1.0.3 through 1.7.0. Exploitation requires that the application has overridden the sanitizer's default allowed tags to include SVG reference elements such as use or feImage.…

Workaround published by Red Hat

If the sanitizer's allowed tags have been overridden, remove SVG reference elements such as use and feImage from that list. Applications using the default allowed tags are not affected. Upgrade to rails-html-sanitizer 1.7.1 or later where a fix is available.

Source: Red Hat security advisory for CVE-2026-73648 (CC BY 4.0)

Frequently Asked Questions

## 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](https://github.com/flavorjones/loofah/security/advisories/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 `SVG_ALLOW_LOCAL_HREF` collection to local, same-document refer

O3 Security · Impact-Aware SCA

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