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.
- 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
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
Which versions are affected by CVE-2026-44665?
2 open source packages ship an affected version, including fast-xml-builder.
| Package | 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.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-44665 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44665 exists.
Sources
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 and 7 more.