EEF-CVE-2026-47080 CVE-2026-47080 GHSA-67r9-hmxw-h595
CDATA Section Breakout via Unsanitised ]]> in xml_builder
- Severity
- 0.0 / 10
- Unknown · CVSS 4.0
- Exploit chance (EPSS)
- 0.22%
- Chance of exploitation in the next 30 days. Higher than 12.84% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-91 XML Injection (aka Blind XPath Injection)
- Fix
2.4.1- Upgrade xml_builder to this version or later
Description
Summary
XML Injection vulnerability in joshnuss xml_builder (XmlBuilder module) allows Content Spoofing, XML Injection.
This vulnerability is associated with program files lib/xml_builder.ex and program routines XmlBuilder.generate/1, XmlBuilder.generate/2, XmlBuilder.escape/1.
The escape/1 clause for {:cdata, data} in lib/xml_builder.ex concatenates data verbatim between the CDATA opener <![CDATA[ and closer ]]> without rewriting or splitting on the embedded ]]> sequence. Because CDATA sections have no internal escape mechanism, the only safe way to embed arbitrary bytes is to split on ]]> and emit adjacent CDATA sections. An attacker who can supply input containing ]]> closes the CDATA section early; any bytes that follow are parsed as ordinary XML markup by downstream consumers, allowing injection of arbitrary elements, text, or entity references into the output document.
This issue affects xml_builder: from 0.0.7 before 2.4.1.
Affected versions
Hex
| Package | Vulnerable | Fixed in |
|---|---|---|
| xml_builder | >= 0.0.7, < 2.4.1 |
2.4.1 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
xml_builder Hex → 2.4.1
- mix
{:xml_builder, "~> 2.4.1"} # then: mix deps.update xml_builder
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
- Attack vector
- Local
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- Low
- Availability (subsequent systems)
- None
Weakness
CWE-91: XML Injection (aka Blind XPath Injection)
The product does not properly neutralize special elements that are used in XML, allowing attackers to modify the syntax, content, or commands of the XML before it is processed by an end system.
How to prevent it
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
References
Advisories
Fixes and patches
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| EEF-CVE-2026-47079 Round-trip Corruption via Improper Entity Escaping in xml_builder | Not rated yet | Also affects xml_builder |
| EEF-CVE-2026-48590 Element and Attribute Names Injected Verbatim into XML Output in xml_builder | Not rated yet | Also affects xml_builder |
| GHSA-vr34-hp96-76pp xmldom: requireWellFormed DocType publicId/systemId validation is bypassable via an embedded line terminator | High | Same weakness, CWE-91 |
| GHSA-jxjr-3g7g-3944 xmldom: requireWellFormed element/attribute name validation is bypassable via an embedded line terminator | High | Same weakness, CWE-91 |
| GHSA-c7q8-3ch8-vqpv xmldom: Processing Instruction Target Injection Bypasses requireWellFormed | High | Same weakness, CWE-91 |
| GHSA-3px3-54cx-rmw9 xmldom: Creation-time XML Name/QName validation is bypassable via an embedded line terminator, allowing injection on the default serialization path | High | Same weakness, CWE-91 |
| GHSA-27p8-2357-5qqv xmldom: DocType `name` Injection Bypasses requireWellFormed | High | Same weakness, CWE-91 |
| GHSA-w2rr-34g9-rvrj xmldom: Element name injection via createElement() bypasses requireWellFormed | High | Same weakness, CWE-91 |
Credits: Jonatan Männchen / EEF, Joshua Nussbaum, Peter Ullrich
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