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

CVE-2026-83619 is fixed in node-xmldom on 1 platform, first by DEBIAN-CVE-2026-83619, released September 2, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-83619
- Priority: High
- CVSS: n/a (Important)
- EPSS: 0.0052
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 1, 2026
- Weakness: Uncontrolled Resource Consumption
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83619

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-xmldom Debian 13.5 (trixie) | 0.9.5-1 | [DEBIAN-CVE-2026-83619](https://patchblox.com/security/data/fix/linux/debian-cve-2026-83619.md) | Sep 2, 2026 |
| Linux | node-xmldom Debian 14 | 0.9.5-1 | [DEBIAN-CVE-2026-83619](https://patchblox.com/security/data/fix/linux/debian-cve-2026-83619.md) | Sep 2, 2026 |

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Data as of 2026-11-09T19:38:12Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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