fkie_cve-2025-46734
Vulnerability from fkie_nvd
Published
2025-05-05 20:15
Modified
2025-05-05 20:54
Severity ?
Summary
league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as `html_input: 'strip'` and `allow_unsafe_links: false` to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with `on` are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added `href` and `src` attributes now respect the existing `allow_unsafe_links` configuration option. If upgrading is not feasible, please consider disabling the `AttributesExtension` for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as `html_input: \u0027strip\u0027` and `allow_unsafe_links: false` to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with `on` are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added `href` and `src` attributes now respect the existing `allow_unsafe_links` configuration option. If upgrading is not feasible, please consider disabling the `AttributesExtension` for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier."
},
{
"lang": "es",
"value": "league/commonmark es un analizador de PHP Markdown. Una vulnerabilidad de cross-site scripting (XSS) en la extensi\u00f3n Attributes de la librer\u00eda league/commonmark (versiones 1.5.0 a 2.6.x) permite a atacantes remotos insertar llamadas JavaScript maliciosas en HTML. La librer\u00eda league/commonmark ofrece opciones de configuraci\u00f3n como `html_input: \u0027strip\u0027` y `allow_unsafe_links: false` para mitigar los ataques de cross-site scripting (XSS) eliminando HTML sin formato y deshabilitando enlaces no seguros. Sin embargo, al habilitar la extensi\u00f3n Attributes, los usuarios pueden inyectar atributos HTML arbitrarios en elementos mediante la sintaxis Markdown, utilizando llaves. La versi\u00f3n 2.7.0 incluye tres cambios para prevenir este vector de ataque XSS: todos los atributos que empiezan por `on` se consideran no seguros y se bloquean por defecto; se admite una lista expl\u00edcita de atributos HTML permitidos; y los atributos `href` y `src` a\u00f1adidos manualmente ahora respetan la opci\u00f3n de configuraci\u00f3n `allow_unsafe_links`. Si la actualizaci\u00f3n no es posible, considere deshabilitar `AttributesExtension` para usuarios no confiables y/o filtrar el HTML renderizado a trav\u00e9s de una librer\u00eda como HTMLPurifier."
}
],
"id": "CVE-2025-46734",
"lastModified": "2025-05-05T20:54:19.760",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 6.4,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
"version": "3.1"
},
"exploitabilityScore": 3.1,
"impactScore": 2.7,
"source": "security-advisories@github.com",
"type": "Secondary"
}
]
},
"published": "2025-05-05T20:15:21.613",
"references": [
{
"source": "security-advisories@github.com",
"url": "https://github.com/thephpleague/commonmark/commit/f0d626cf05ad3e99e6db26ebcb9091b6cd1cd89b"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/thephpleague/commonmark/security/advisories/GHSA-3527-qv2q-pfvx"
}
],
"sourceIdentifier": "security-advisories@github.com",
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-79"
}
],
"source": "security-advisories@github.com",
"type": "Primary"
}
]
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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