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

> An attacker can cause a denial of service by submitting crafted XML input that triggers quadratic backtracking in the xmldom parser, stalling the application.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Sep 2026
- **Updated:** 1 Sep 2026
- **Also known as:** AZL-99336, CLEANSTART-2026-NW59337, DEBIAN-CVE-2026-83619, ECHO-a029-6e2a-1037, GHSA-x4fp-j954-r2f4, MINI-36jg-fcj9-6pwc, MINI-h529-79j9-x47g, MINI-hch3-gcwh-p6r2, MINI-m54g-qq8g-r95c, ROOT-APP-NPM-CVE-2026-83619, UBUNTU-CVE-2026-83619

## What is CVE-2026-83619?

CVE-2026-83619 is a high-severity denial of service vulnerability in @xmldom xmldom, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-400 (Uncontrolled Resource Consumption), CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2026-83619?

2 open source packages ship an affected version, including @xmldom/xmldom.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@xmldom/xmldom` | npm | From 0.7.0 | 0.8.15 |
| `@xmldom/xmldom` | npm | From 0.7.0 | 0.8.15 |

## How do I fix CVE-2026-83619?

Upgrade @xmldom/xmldom to 0.8.15 or later.

## Is CVE-2026-83619 being exploited?

There is no known exploitation of CVE-2026-83619 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-83619 and fix it if it is affected.

What it is: CVE-2026-83619 is a high-severity denial of service vulnerability in @xmldom xmldom, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-83619 in the wild and no public exploit code.

Affected packages and fixed versions:
- @xmldom/xmldom (npm): affected from 0.7.0; fixed in 0.8.15
- @xmldom/xmldom (npm): affected from 0.7.0; fixed in 0.8.15

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-83619/ (Markdown: https://insights.sbomify.com/CVE-2026-83619/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-83619
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-83619
- OSV: https://osv.dev/vulnerability/CVE-2026-83619

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-83619/
Summaries are generated and may contain mistakes; the official description above is the record.