What’s Vulnerable › Vulnerabilities

CVE-2026-83619: xmldom: End-tag Whitespace-Trim Regex ReDoS — quadratic backtracking in the 0.8.x end-tag parser

• Severity: high (CVSS 8.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-01 · updated 2026-09-08
• Weakness: CWE-400

Description

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.7.0 until 0.8.15, the release-0.8.x parser in lib/sax.js trims captured end-tag names with the unanchored global expression /[ \t\n\r]+$/g. For an end tag containing a long whitespace run followed by a non-whitespace character, the expression retries from each possible starting position and backtracks quadratically before failing its end anchor. DOMParser.parseFromString() reaches the path under default options, allowing a small unauthenticated XML input to stall the Node.js event loop; the 0.9.x and unscoped npm lines do not contain this expression. This issue is fixed in @xmldom/xmldom version 0.8.15.

Affected products

• xmldom: from 0.7.0, < 0.8.15

References

• https://github.com/xmldom/xmldom/commit/3abb0934f5a8a84d83a1f9cde0f2bd04c08b2a09
• https://github.com/xmldom/xmldom/pull/1072
• https://github.com/xmldom/xmldom/releases/tag/0.8.15
• https://github.com/xmldom/xmldom/security/advisories/GHSA-x4fp-j954-r2f4

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