xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. Prior to @xmldom/xmldom versions 0.8.14 and 0.9.11, and in xmldom version 0.6.0 and earlier, Document.createElement(tagName) stores an unvalidated element name and XMLSerializer.serializeToString() emits that name verbatim. The requireWellFormed: true path did not validate the element qualified name or synthesized xmlns:PREFIX declaration, so attacker-controlled tag names could inject attributes, elements, or processing instructions into serialized XML or HTML and could cause cross-site scripting when browser-consumed. The unchecked values violate the XML QName constraint, and default serialization and creation-time createElement() behavior remain permissive. This issue is fixed in @xmldom/xmldom versions 0.8.14 and 0.9.11; no fixed version is available for xmldom.
Weakness
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.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Red Hat Developer Hub 1.9 | RedHat | rhdh/rhdh-hub-rhel9:1789554285 | * |
| Node-xmldom | Ubuntu | upstream | * |
Potential Mitigations
- 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.
Related Attack Patterns
References
- https://github.com/xmldom/xmldom/commit/cba1321218b069182695813fa7565653708e172e
- https://github.com/xmldom/xmldom/commit/d8212e632507eaf1d9f609657dd4c56abeb12d44
- https://github.com/xmldom/xmldom/pull/1043
- https://github.com/xmldom/xmldom/pull/1050
- https://github.com/xmldom/xmldom/releases/tag/0.8.14
- https://github.com/xmldom/xmldom/releases/tag/0.9.11
- https://github.com/xmldom/xmldom/security/advisories/GHSA-w2rr-34g9-rvrj
- https://github.com/xmldom/xmldom/security/advisories/GHSA-w2rr-34g9-rvrj