---
id: CVE-2026-47079
title: >-
  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 routin…
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 routin…
severity: none
cwe:
  - CWE-838
published: '2026-08-21'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:10:00.103'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-47079'
references:
  - url: 'https://cna.erlef.org/cves/CVE-2026-47079.html'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/joshnuss/xml_builder/commit/c3390e2046ec297b3bb8c30d5779cdfd6508c275
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/joshnuss/xml_builder/security/advisories/GHSA-5hjx-8g53-cmvm
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-47079'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/joshnuss/xml_builder/security/advisories/GHSA-5hjx-8g53-cmvm
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00189
epssPercentile: 0.08438
ingestedAt: '2026-10-27T18:52:09.900Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.