# CVE-2026-83608: xmldom: DocType `name` Injection Bypasses requireWellFormed

> Attackers can inject malicious markup via DocumentType name in xmldom when requireWellFormed is enabled, potentially leading to code execution or data exposure.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/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:** 4 Sep 2026
- **Also known as:** AZL-99345, CLEANSTART-2026-IC19536, DEBIAN-CVE-2026-83608, ECHO-a025-84a9-6cfd, GHSA-27p8-2357-5qqv, MINI-f7rj-58xf-g8m4, MINI-pfwg-qgwr-4f45, MINI-vcg2-qr97-qh7w, MINI-x6hj-74r7-vqm3, ROOT-APP-NPM-CVE-2026-83608, UBUNTU-CVE-2026-83608

## What is CVE-2026-83608?

CVE-2026-83608 is a high-severity 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. Prior to @xmldom/xmldom versions 0.8.15 and 0.9.12, and in xmldom version 0.6.0 and earlier, the DOCUMENT_TYPE_NODE branch in lib/dom.js validates publicId, systemId, and internalSubset under requireWellFormed: true but emits DocumentType.name verbatim. A name containing > or whitespace can terminate the <!DOCTYPE ...> declaration and inject sibling markup; the value can be supplied through createDocumentType() on the 0.8.x and unscoped lines or through a direct DocumentType.name property write on every affected line. The default path and legacy creation-time behavior remain permissive, while the vulnerable strict path fails to enforce an XML Name. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; no fixed version is available for xmldom.

Weakness: CWE-91 (XML Injection)

## Which versions are affected by CVE-2026-83608?

6 open source packages ship an affected version, including @xmldom/xmldom and 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 |
| `@xmldom/xmldom` | npm | From 0.9.0 | 0.9.12 |
| `@xmldom/xmldom` | npm | From 0.9.0 | 0.9.12 |
| `xmldom` | npm | All versions to 0.6.0 | None |
| `xmldom` | npm | All versions to 0.6.0 | None |

## How do I fix CVE-2026-83608?

Upgrade @xmldom/xmldom to a fixed version for your release line: 0.8.15 or 0.9.12.

## Is CVE-2026-83608 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-83608 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-83608 and fix it if it is affected.

What it is: CVE-2026-83608 is a high-severity 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-83608 exists.

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
- @xmldom/xmldom (npm): affected from 0.9.0; fixed in 0.9.12
- @xmldom/xmldom (npm): affected from 0.9.0; fixed in 0.9.12
- xmldom (npm): affected all versions up to 0.6.0; no fix listed
- xmldom (npm): affected all versions up to 0.6.0; no fix listed

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-2026-83608/ (Markdown: https://insights.sbomify.com/CVE-2026-83608/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-83608
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-83608
- OSV: https://osv.dev/vulnerability/CVE-2026-83608

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-83608/
Summaries are generated and may contain mistakes; the official description above is the record.