Junglewise Threat Intelligence

CVE-2026-34601: xmldom XML injection via unsafe CDATA serialization

CVE-2026-34601 · Severity: high · CVSS 7.5 · Published 2026-04-02

Technologies: Xmldom @Xmldom/Xmldom, Xmldom.

Executive brief

xmldom is a JavaScript library used to process and create XML documents. A security flaw allows attackers to insert special characters that break out of protected text areas, effectively injecting new commands or data into the XML structure. This can lead to the manipulation of business logic in applications that rely on this library to handle data securely.

Technical details

The vulnerability is classified as XML Injection (CWE-91) within the xmldom library's XMLSerializer and DOMParser components. The root cause is the failure to reject or safely split the CDATA terminator sequence ']]>' when it appears within a CDATASection node. An attacker can provide a string containing this sequence via methods like createCDATASection, appendData, or textContent. During serialization, the XMLSerializer emits the content verbatim, allowing the attacker to close the CDATA section prematurely and inject arbitrary XML tags. This can be exploited remotely if the application processes untrusted input through these DOM methods. The issue is patched in xmldom 0.6.0, @xmldom/xmldom 0.8.12, and @xmldom/xmldom 0.9.9.

Affected products

  • xmldom xmldom <= 0.6.0
  • xmldom @xmldom/xmldom < 0.8.12, >= 0.9.0 < 0.9.9

Timeline

  • 2026-03-29: patched: Fixes committed and releases 0.8.12 and 0.9.9 published.
  • 2026-03-29: advisory: GitHub Security Advisory GHSA-wh4c-j3r5-mjhp published.
  • 2026-04-02: disclosed: CVE-2026-34601 published.

References