CVE-2026-66370
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 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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
2cpe:2.3:a:rrrene:htmlsanitizeex:*:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:rrrene:htmlsanitizeex:*:*:*:*:*:*:*:*range: >=0.3.1,<1.5.3
- (no CPE)range: from 0.3.1 before 1.4.5 and from 1.5.0-rc.0 before 1.5.3
Patches
Vulnerability mechanics
References
5- cna.erlef.org/cves/CVE-2026-66370.htmlnvdPatchThird Party Advisory
- github.com/rrrene/html_sanitize_ex/commit/a1e804ed997e780ea71d14393cf2f701330553a6nvdPatch
- osv.dev/vulnerability/EEF-CVE-2026-66370nvdPatchThird Party Advisory
- github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-w3f9-jjhw-wwvqnvdBroken Link
- github.com/rrrene/html_sanitize_ex/commit/21394e758cb0ffe12fb9953c30fdedc6016c8f9envd
News mentions
0No linked articles in our index yet.