CVE-2026-126209

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Source
https://cve.org/CVERecord?id=CVE-2026-126209
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-126209.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-126209
Aliases
Downstream
CGA (9)
Published
2026-11-12T21:01:58Z
Modified
2026-11-13T10:46:14Z
Severity
  • 5.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N CVSS Calculator
Summary
Loofah allowed_uri? treats javascript&#x3a alert(1) as safe
Details

Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. From 2.25.0 until 2.25.3, Loofah::HTML5::Scrub.allowed_uri? strips whitespace and control characters before decoding a semicolon-less numeric character reference, changing where the reference ends and hiding a javascript: or vbscript: scheme that a browser reconstructs. The bypass applies to encoded colons and encoded scheme letters when a stripped character terminates the numeric reference. An application that renders the approved value in href or another browser-interpreted URI attribute can allow cross-site scripting, and Rails::HTML::Sanitizer.allowed_uri? re-exports the affected helper. Loofah's default sanitize() path is not affected because Nokogiri decodes entities before URI evaluation. This issue is fixed in version 2.25.3.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-184",
        "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126209.json"
}
References

Affected packages

Git / github.com/flavorjones/loofah

Affected ranges

Type
GIT
Repo
https://github.com/flavorjones/loofah
Events
Introduced
e65bdddfd3381f3a131be7e137d89bb3959c072b
Fixed
bbe007e52e8aeaa520b3e515235d467f5b1416e6
Fixed
62c04841e8252a1b5373afcd2b89fb9b8279e317
Database specific
Show details 
{
    "extracted_events": [
        {
            "range": [
                {
                    "introduced": "2.25.0"
                },
                {
                    "fixed": "2.25.3"
                }
            ],
            "source": "AFFECTED_FIELD",
            "strategy": "StringRangeExpression"
        },
        {
            "range": [
                {
                    "fixed": "62c04841e8252a1b5373afcd2b89fb9b8279e317"
                }
            ],
            "source": "REFERENCES_COMMIT"
        },
        {
            "original_tag": "v2.25.3",
            "range": [
                {
                    "fixed": "bbe007e52e8aeaa520b3e515235d467f5b1416e6"
                }
            ],
            "source": "REFERENCES_TAG"
        }
    ]
}

Affected versions

v2.*
v2.25.0
v2.25.1
v2.25.2

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-126209.json"