Vulnerability · Published Aug 6, 2026 · Assigned by EEF

CVE-2026-66829html_sanitize_ex HTML5 scrubber keeps attacker-supplied meta refresh, allowing forced cross-origin redirection

Low 2.3

In plain English

A low-severity open redirect in html_sanitize_ex from rrrene. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities).

Severity (CVSS 4.0)2.3Low

Exploit odds (30 days)0.6%top 52.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to force visitors of a page to navigate to a site of the attacker's choosing via a <meta http-equiv="refresh"> element in sanitized HTML. HtmlSanitizeEx.html5/1 keeps attacker-supplied <meta> elements in its output. A meta element acts on the whole document rather than on the fragment it was embedded in, so it can also declare document-wide directives such as Content-Security-Policy. This is not cross-site scripting. Browsers do not navigate a meta refresh to a javascript: URL, so the uppercase JAVASCRIPT: filter bypass yields no script execution and none was demonstrated. This issue affects html_sanitize_ex: from 0.3.1 before 1.4.5 and from 1.5.0-rc.0 before 1.5.3.

Affected products (as reported)

Vendor	Product	Versions
rrrene	html_sanitize_ex	0.3.1 – before 1.4.51.5.0-rc.0 – before 1.5.3
rrrene	html_sanitize_ex	8976d64ea0b77d26093a94a43ec48a3978e8d028 – before *

Weakness: CWE-601 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

In plain English

Official description

Affected products (as reported)

References