CVE-2026-66370

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Source
https://cve.org/CVERecord?id=CVE-2026-66370
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-66370.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-66370
Aliases
Published
2026-08-06T14:49:15.841Z
Modified
2026-08-09T03:30:29.514317686Z
Severity
  • 4.8 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N CVSS Calculator
Summary
html_sanitize_ex HTML5 scrubber keeps attacker-supplied form-association attributes, allowing form hijacking
Details

URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene htmlsanitizeex 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 htmlsanitizeex: from 0.3.1 before 1.5.3.

Database specific 
{
    "cna_assigner": "EEF",
    "cwe_ids": [
        "CWE-601"
    ],
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "introduced": "8976d64ea0b77d26093a94a43ec48a3978e8d028"
                },
                {
                    "fixed": "a1e804ed997e780ea71d14393cf2f701330553a6"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66370.json"
}
References

Affected packages

Git / github.com/rrrene/html_sanitize_ex

Affected ranges

Type
GIT
Repo
https://github.com/rrrene/html_sanitize_ex
Events
Introduced
088f92b18a4a3911a862b527d5eb3713f9abac24
Fixed
f25255c82a3c6034a57d934718e10c982d29fa31
Fixed
a1e804ed997e780ea71d14393cf2f701330553a6
Database specific 
{
    "extracted_events": [
        {
            "introduced": "0.3.1"
        },
        {
            "fixed": "1.5.3"
        }
    ],
    "source": [
        "DESCRIPTION",
        "REFERENCES"
    ]
}

Affected versions

v0.*
v0.3.1
v1.*
v1.0.0
v1.0.1
v1.2.0
v1.4.1
v1.4.2
v1.4.3
v1.4.4
v1.5.0
v1.5.0-rc.0
v1.5.1
v1.5.2

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-66370.json"