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 1.4.5 and from 1.5.0-rc.0 before 1.5.3.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
rrrene html_sanitize_ex
Default version status: unaffected
0.3.1 to < 1.4.5affected1.5.0-rc.0 to < 1.5.3affected
pkg:hex/html_sanitize_exrrrene html_sanitize_ex
Default version status: unaffected
8976d64ea0b77d26093a94a43ec48a3978e8d028 to < *affected
pkg:github/rrrene/html_sanitize_exReferences
- https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-w3f9-jjhw-wwvq ↗
- https://cna.erlef.org/cves/CVE-2026-66370.html ↗
- https://osv.dev/vulnerability/EEF-CVE-2026-66370 ↗
- https://github.com/rrrene/html_sanitize_ex/commit/a1e804ed997e780ea71d14393cf2f701330553a6 ↗
- https://github.com/rrrene/html_sanitize_ex/commit/21394e758cb0ffe12fb9953c30fdedc6016c8f9e ↗