GHSA-52MM-H59V-F3C7
Vulnerability from github – Published: 2026-06-17 18:35 – Updated: 2026-06-18 14:47Improper Neutralization of Script in Attributes in a Web Page vulnerability in pragdave earmark allows stored cross-site scripting via unescaped HTML attribute values.
'Elixir.Earmark.Transform':_make_att1/2 in lib/earmark/transform.ex splices attribute values verbatim between two literal " bytes: [" ", name, "=\"", value, "\""]. Text nodes are routed through the existing escape function which encodes " as ", but attribute values never visit that path. A markdown link whose URL or title contains a bare " closes the attribute early and lets the trailing bytes be parsed by the browser as fresh HTML attributes. For example, click.
The earmark library is no longer maintained and has been retired on Hex. No patched version will be released. All releases from 1.4.1 onward are affected, and users should migrate to a maintained Markdown library such as MDEx.
This issue affects earmark from 1.4.1 onward.
{
"affected": [
{
"package": {
"ecosystem": "Hex",
"name": "earmark"
},
"ranges": [
{
"events": [
{
"introduced": "1.4.1"
},
{
"last_affected": "1.5.0-pre1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-48591"
],
"database_specific": {
"cwe_ids": [
"CWE-79",
"CWE-83"
],
"github_reviewed": true,
"github_reviewed_at": "2026-06-18T14:47:16Z",
"nvd_published_at": "2026-06-17T18:18:04Z",
"severity": "MODERATE"
},
"details": "Improper Neutralization of Script in Attributes in a Web Page vulnerability in pragdave earmark allows stored cross-site scripting via unescaped HTML attribute values.\n\n\u0027Elixir.Earmark.Transform\u0027:_make_att1/2 in lib/earmark/transform.ex splices attribute values verbatim between two literal \" bytes: [\" \", name, \"=\\\"\", value, \"\\\"\"]. Text nodes are routed through the existing escape function which encodes \" as \u0026quot;, but attribute values never visit that path. A markdown link whose URL or title contains a bare \" closes the attribute early and lets the trailing bytes be parsed by the browser as fresh HTML attributes. For example, [click](http://example.com/?a=x\" onerror=\"alert(1)) renders as \u003ca href=\"http://example.com/?a=x\" onerror=\"alert(1)\"\u003eclick\u003c/a\u003e, executing arbitrary JavaScript in the victim\u0027s browser.\n\nThe earmark library is no longer maintained and has been retired on Hex. No patched version will be released. All releases from 1.4.1 onward are affected, and users should migrate to a maintained Markdown library such as MDEx.\n\nThis issue affects earmark from 1.4.1 onward.",
"id": "GHSA-52mm-h59v-f3c7",
"modified": "2026-06-18T14:47:16Z",
"published": "2026-06-17T18:35:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48591"
},
{
"type": "WEB",
"url": "https://cna.erlef.org/cves/CVE-2026-48591.html"
},
{
"type": "PACKAGE",
"url": "https://github.com/pragdave/earmark"
},
{
"type": "WEB",
"url": "https://osv.dev/vulnerability/EEF-CVE-2026-48591"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "earmark: Stored XSS via unescaped HTML attribute values"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.