URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to retarget a form already on the rendering page and receive whatever the victim submits, including credentials, via the form and formaction attributes on an <input> element in sanitized HTML. HTML's form attribute associates an input with any form on the page by its id even when the input sits outside that form, and formaction on a submit control overrides the owning form's action. Neither attribute receives a scheme check, so an absolute cross-origin URL survives sanitizing.
No script executes. The scrubber allows neither form nor button, so the attacker cannot introduce a form of their own and the rendering page must already contain a form carrying an id.
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.
Metrics
Affected Vendors & Products
References
History
Wed, 19 Aug 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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Wed, 19 Aug 2026 12:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to retarget a form already on the rendering page and receive whatever the victim submits, including credentials, via the form and formaction attributes on an <input> element in sanitized HTML. HTML's form attribute associates an input with any form on the page by its id even when the input sits outside that form, and formaction on a submit control overrides the owning form's action. Neither attribute receives a scheme check, so an absolute cross-origin URL survives sanitizing. No script executes. The scrubber allows neither form nor button, so the attacker cannot introduce a form of their own and the rendering page must already contain a form carrying an id. This issue affects html_sanitize_ex: from 0.3.1 before 1.5.3. | URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to retarget a form already on the rendering page and receive whatever the victim submits, including credentials, via the form and formaction attributes on an <input> element in sanitized HTML. HTML's form attribute associates an input with any form on the page by its id even when the input sits outside that form, and formaction on a submit control overrides the owning form's action. Neither attribute receives a scheme check, so an absolute cross-origin URL survives sanitizing. No script executes. The scrubber allows neither form nor button, so the attacker cannot introduce a form of their own and the rendering page must already contain a form carrying an id. 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. |
| References |
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Tue, 11 Aug 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Rrrene htmlsanitizeex
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| CPEs | cpe:2.3:a:rrrene:htmlsanitizeex:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Rrrene htmlsanitizeex
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| Metrics |
cvssV3_1
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Thu, 06 Aug 2026 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to retarget a form already on the rendering page and receive whatever the victim submits, including credentials, via the form and formaction attributes on an <input> element in sanitized HTML. HTML's form attribute associates an input with any form on the page by its id even when the input sits outside that form, and formaction on a submit control overrides the owning form's action. Neither attribute receives a scheme check, so an absolute cross-origin URL survives sanitizing. No script executes. The scrubber allows neither form nor button, so the attacker cannot introduce a form of their own and the rendering page must already contain a form carrying an id. This issue affects html_sanitize_ex: from 0.3.1 before 1.5.3. | |
| Title | html_sanitize_ex HTML5 scrubber keeps attacker-supplied form-association attributes, allowing form hijacking | |
| First Time appeared |
Rrrene
Rrrene html Sanitize Ex |
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| Weaknesses | CWE-601 | |
| CPEs | cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Rrrene
Rrrene html Sanitize Ex |
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| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: EEF
Published: 2026-08-06T14:49:15.841Z
Updated: 2026-08-19T11:51:08.771Z
Reserved: 2026-08-06T10:15:01.808Z
Link: CVE-2026-66370
Updated: 2026-08-06T15:42:06.830Z
Status : Modified
Published: 2026-08-06T16:16:48.420
Modified: 2026-08-19T12:18:34.240
Link: CVE-2026-66370
No data.