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
2026-08-06T14:49:15Z
Modified
2026-08-22T03:58:09Z
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 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.

Database specific 
{
    "cna_assigner": "EEF",
    "cwe_ids": [
        "CWE-601"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66370.json",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "introduced": "8976d64ea0b77d26093a94a43ec48a3978e8d028"
                },
                {
                    "fixed": "*"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ]
}
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
21394e758cb0ffe12fb9953c30fdedc6016c8f9e
Fixed
a1e804ed997e780ea71d14393cf2f701330553a6
Database specific
Show details 
{
    "cpe": "cpe:2.3:a:rrrene:htmlsanitizeex:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "0.3.1"
        },
        {
            "fixed": "1.5.3"
        }
    ],
    "source": [
        "CPE_RANGE",
        "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"