CVE-2026-47079

Summary

Inappropriate Encoding for Output Context vulnerability in joshnuss xml_builder (XmlBuilder module) allows Content Spoofing, Cross-site Scripting.

This vulnerability is associated with program files lib/xml_builder.ex and program routines XmlBuilder.generate/1, XmlBuilder.generate/2, XmlBuilder.escape_string/1, XmlBuilder.escape_entity/1.

XmlBuilder.generate/1 does not escape literal & characters in text or attribute values when they are followed by an entity-like token (lt;, gt;, amp;, quot;, apos;). As a result, attacker-supplied input such as &lt;script&gt; is emitted verbatim into the serialized XML rather than being escaped to &amp;lt;script&amp;gt;. When a downstream XML parser later reads the document, it decodes the entity sequences into the literal characters <script>, promoting inert-looking text into real markup. This allows an attacker to bypass upstream filters that block raw < and > characters, injecting markup into any downstream consumer that parses the produced XML and renders the text content in a markup-sensitive context (HTML, SVG, RSS/Atom feeds). Both element text and attribute values are affected.

This issue affects xml_builder: from 0.0.6 before 2.4.1.

Affected Software

VendorProductVersion RangeStatus
joshnussxml_builder0.0.6 < 2.4.1affected
joshnussxml_builderaae31e6e8ac837bcbb8afb816c0d14324b5cfe2b < c3390e2046ec297b3bb8c30d5779cdfd6508c275affected

Weaknesses

  • CWE-838: CWE-838 Inappropriate Encoding for Output Context

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

Additional References

References