# CVE-2026-44665: fast-xml-builder: Attribute values with unwanted quotes can bypass malicious or unwanted attributes

> Attackers can inject malicious attributes into generated XML/HTML by exploiting quote handling flaws, potentially leading to XSS or security bypasses.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 13 May 2026
- **Updated:** 18 May 2026
- **Also known as:** ECHO-b6ab-01c5-6ad1, GHSA-5wm8-gmm8-39j9, MINI-227m-vfqp-vgc2, MINI-3rq9-8j76-hgc3, MINI-8vxv-3rj4-v7xr, MINI-9gjr-hg67-9mv6, MINI-gg3c-vgmg-52r8, MINI-qjqc-x249-8g93, MINI-r62h-v592-rmg8, MINI-rxfq-f267-rwcg, MINI-vh8f-3chw-24vj, MINI-vr98-8qhf-8jgh, ROOT-APP-NPM-CVE-2026-44665

## What is CVE-2026-44665?

CVE-2026-44665 is a medium-severity cross-site scripting vulnerability in NaturalIntelligence fast-xml-builder, published on 13 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

fast-xml-builder builds XML from JSON. Prior to 1.1.7, when an input data has quotes in attribute values but process entities is not enabled, it breaks the attribute value into multiple attributes. This gives the room for an attacker to insert unwanted attributes to the XML/HTML. This vulnerability is fixed in 1.1.7.

Weakness: CWE-91 (XML Injection)

## Which versions are affected by CVE-2026-44665?

2 open source packages ship an affected version, including fast-xml-builder.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `fast-xml-builder` | npm | All versions | 1.1.7 |
| `fast-xml-builder` | npm | All versions | 1.1.7 |

## How do I fix CVE-2026-44665?

Upgrade fast-xml-builder to 1.1.7 or later.

## Is CVE-2026-44665 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44665 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44665 and fix it if it is affected.

What it is: CVE-2026-44665 is a medium-severity cross-site scripting vulnerability in NaturalIntelligence fast-xml-builder, published on 13 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44665 exists.

Affected packages and fixed versions:
- fast-xml-builder (npm): affected all versions; fixed in 1.1.7
- fast-xml-builder (npm): affected all versions; fixed in 1.1.7

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-2026-44665/ (Markdown: https://insights.sbomify.com/CVE-2026-44665/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44665
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44665
- OSV: https://osv.dev/vulnerability/CVE-2026-44665

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44665/
Summaries are generated and may contain mistakes; the official description above is the record.