CVE-2026-47079

Round-trip Corruption via Improper Entity Escaping in xml_builder

LOW
2.1
CVSS Score
Published: August 21, 2026 at 09:52 AM UTC
Updated: October 16, 2026 at 03:10 PM UTC
1 product affected across 1 vendorXML Builder

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Severity
LOW2.1
Exploit prediction
EPSS 0.2%
SSVC
PoC

Description

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions0.0.6aae31e6e8ac837bcbb8afb816c0d14324b5cfe2b
Vendor states this is fixed in c3390e2046ec297b3bb8c30d5779cdfd6508c275 (fixed)
Affected range stops below 2.4.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

2.1LOWEEF
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-838

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