URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to force… (CVE-2026-66829)
CVE-2026-66829 is a low-severity open redirect vulnerability in the html_sanitize_ex library's HTML5 scrubber. It allows remote attackers to cause users to navigate to attacker-chosen sites via a <meta http-equiv="refresh"> element in sanitized HTML output. This is not a cross-site scripting issue, as script execution is not possible through this vector. The vulnerability affects versions from 0.3.1 up to but not including 1.5.3, including 1.5.0-rc.0. No official patch or fix is currently documented.
AI Analysis
Technical Summary
The vulnerability in rrrene html_sanitize_ex's HTML5 scrubber allows attacker-supplied <meta http-equiv="refresh"> elements to be retained in sanitized HTML output. Because a meta refresh element affects the entire document, it can redirect users to arbitrary URLs controlled by an attacker. This does not enable script execution since browsers do not navigate meta refresh to javascript: URLs, and no cross-site scripting was demonstrated. Affected versions include >=0.3.1 <1.5.3 and specifically 0.3.1 and 1.5.0-rc.0. The CVSS v3.1 score is 2.3, indicating low severity.
Potential Impact
An attacker can cause users visiting a page that uses the vulnerable html_sanitize_ex versions to be redirected to arbitrary external sites via a meta refresh element. This could facilitate phishing or redirect users to malicious sites, but does not allow script execution or compromise the original site directly.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should consider filtering or removing meta refresh elements from sanitized HTML output as a temporary mitigation.
URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to force… (CVE-2026-66829)
Description
CVE-2026-66829 is a low-severity open redirect vulnerability in the html_sanitize_ex library's HTML5 scrubber. It allows remote attackers to cause users to navigate to attacker-chosen sites via a <meta http-equiv="refresh"> element in sanitized HTML output. This is not a cross-site scripting issue, as script execution is not possible through this vector. The vulnerability affects versions from 0.3.1 up to but not including 1.5.3, including 1.5.0-rc.0. No official patch or fix is currently documented.
CVSS v3.1
Score 6.1medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in rrrene html_sanitize_ex's HTML5 scrubber allows attacker-supplied <meta http-equiv="refresh"> elements to be retained in sanitized HTML output. Because a meta refresh element affects the entire document, it can redirect users to arbitrary URLs controlled by an attacker. This does not enable script execution since browsers do not navigate meta refresh to javascript: URLs, and no cross-site scripting was demonstrated. Affected versions include >=0.3.1 <1.5.3 and specifically 0.3.1 and 1.5.0-rc.0. The CVSS v3.1 score is 2.3, indicating low severity.
Potential Impact
An attacker can cause users visiting a page that uses the vulnerable html_sanitize_ex versions to be redirected to arbitrary external sites via a meta refresh element. This could facilitate phishing or redirect users to malicious sites, but does not allow script execution or compromise the original site directly.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should consider filtering or removing meta refresh elements from sanitized HTML output as a temporary mitigation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-c486-5fvq-fp3v
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-66829"]
- Database Specific Severity
- LOW
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a7b6fd2bf8831d5393ea5b9
Added to database: 08/11/2026, 18:54:10 UTC
Last enriched: 08/19/2026, 15:06:05 UTC
Last updated: 09/25/2026, 01:47:44 UTC
Views: 72
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