CVE-2026-66843

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Source
https://cve.org/CVERecord?id=CVE-2026-66843
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-66843.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-66843
Aliases
Published
2026-08-06T14:48:20.513Z
Modified
2026-08-09T03:30:50.531078422Z
Severity
  • 2.3 (Low) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N CVSS Calculator
Summary
html_sanitize_ex HTML5 scrubber keeps attacker-supplied `<object>` elements, allowing untrusted content embedding
Details

Inclusion of Functionality from Untrusted Control Sphere vulnerability in the HTML5 scrubber in rrrene htmlsanitizeex allows a remote attacker to load a document of their choosing into a trusted page via the data attribute of an <object> element in sanitized HTML. object is the one URI-bearing element in lib/htmlsanitizeex/scrubber/html5.ex never registered through allowtagwithuriattributes/3, and its only guard is a prefix match on lowercase "javascript:", so mixed-case variants, data: URIs, protocol-relative URLs and same-origin paths all survive.

This is not unconditional cross-site scripting. A javascript: URL does not execute through <object data> in current browsers, data: documents load in an opaque origin, and host-origin script execution additionally requires the application to serve attacker-controlled content from a same-origin path.

This issue affects htmlsanitizeex: from 0.3.1 before 1.5.3.

Database specific 
{
    "unresolved_ranges": [
        {
            "source": "AFFECTED_FIELD",
            "extracted_events": [
                {
                    "introduced": "8976d64ea0b77d26093a94a43ec48a3978e8d028"
                },
                {
                    "fixed": "bec27fec4de99e40c68c4285a610e09e791a3eaf"
                }
            ]
        }
    ],
    "cna_assigner": "EEF",
    "cwe_ids": [
        "CWE-829"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66843.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
bec27fec4de99e40c68c4285a610e09e791a3eaf
Database specific 
{
    "source": [
        "DESCRIPTION",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0.3.1"
        },
        {
            "fixed": "1.5.3"
        }
    ]
}

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-2026-66843.json"