CVE-2026-48591

Description

Improper 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 &quot;, 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 <a href="http://example.com/?a=x" onerror="alert(1)">click</a>, executing arbitrary JavaScript in the victim's browser. The earmark library is no longer maintained and has been retired on Hex.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.

PUBLISHED Reserved 2026-05-22 | Published 2026-06-17 | Updated 2026-06-17 | Assigner EEF

Problem types

CWE-83 Improper Neutralization of Script in Attributes in a Web Page

Product status

Credits

Peter Ullrich finder

Robert Dober remediation developer

Jonatan Männchen / EEF analyst

References

cna.erlef.org/cves/CVE-2026-48591.html related third-party-advisory

osv.dev/vulnerability/EEF-CVE-2026-48591 related

cve.org (CVE-2026-48591)

nvd.nist.gov (CVE-2026-48591)

Download JSON