Is CVE-2026-73492 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-73492 being exploited in the wild.

How severe is CVE-2026-73492?

Medium severity, with a CVSS score of 4, published 12 August 2026.

Which products and versions are affected?

loofah (RubyGems) ECOSYSTEM:introduced=2.25.0,fixed=2.25.2.

Is there a fix for CVE-2026-73492?

Yes. loofah (RubyGems): upgrade to 2.25.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-73492 attacked?

It is attacked over the network.

Am I affected by CVE-2026-73492?

Check whether you run loofah (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-73492: Loofah XSS via malformed URI scheme with numeric character references

CVE-2026-73492 · Severity: medium · CVSS 4 · Published 2026-08-12

Loofah is a Ruby library for sanitizing and manipulating HTML documents. A flaw in its URI validation allows attackers to bypass protections against malicious JavaScript and VBScript URIs by encoding the scheme separator (colon or whitespace) with numeric character references. An attacker can craft HTML that appears safe to Loofah but executes in browsers, potentially leading to cross-site scripting (XSS) attacks on websites using the library.

Technologies: loofah (RubyGems). Vendors: RubyGems.

Quick answers

Is CVE-2026-73492 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-73492 being exploited in the wild.
How severe is CVE-2026-73492?: Medium severity, with a CVSS score of 4, published 12 August 2026.
Which products and versions are affected?: loofah (RubyGems) ECOSYSTEM:introduced=2.25.0,fixed=2.25.2.
Is there a fix for CVE-2026-73492?: Yes. loofah (RubyGems): upgrade to 2.25.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-73492 attacked?: It is attacked over the network.
Am I affected by CVE-2026-73492?: Check whether you run loofah (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

loofah (RubyGems): upgrade to 2.25.2 or later
```
bundle update loofah
```

Technical details

The vulnerability exists in Loofah::HTML5::Scrub.allowed_uri? (versions 2.25.0–2.25.1), which fails to properly decode semicolon-less numeric character references (e.g., &#58, &#9, &#10, &#13) before validating URI schemes. While CGI.unescapeHTML decodes only references with trailing semicolons, browsers decode these malformed references and reconstruct dangerous schemes like javascript: or vbscript:. The flaw only affects callers passing HTML-encoded strings directly to allowed_uri?; the default sanitize() path is unaffected. An attacker must provide HTML input to trigger allowed_uri? validation. The issue was fixed in version 2.25.2 by decoding semicolon-less numeric references before scheme validation.

Affected products

Loofah Loofah 2.25.0 to 2.25.1

Identifiers

CVE-2026-73492
GHSA-5qhf-9phg-95m2

Timeline

2026-08-12: disclosed
2026-07-15: patched: Fix committed and released in version 2.25.2

References

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