Get a Demo

Let's Patch It!

Book a short call with one our specialists, we'll walk you through how Endor Patches work, and ask you a few questions about your environment (like your primary programming languages and repository management). We'll also send you an email right after you fill out the form, feel free to reply with any questions you have in advance!

CVE

CVE-2026-25896

fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names
Back to all
CVE

CVE-2026-25896

fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names

fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. From 4.1.3to before 5.3.5, a dot (.) in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities (<, >, &, ", ') with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered. This vulnerability is fixed in 5.3.5.

Package Versions Affected

Package Version
patch Availability
No items found.

Automatically patch vulnerabilities without upgrading

Fix Without Upgrading
Detect compatible fix
Apply safe remediation
Fix with a single pull request

CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
9.3
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
C
H
U
9.3
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N

Related Resources

No items found.

References

https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.3.5, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25896.json, https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-m7jm-9gc2-mpf2, https://nvd.nist.gov/vuln/detail/CVE-2026-25896, https://github.com/NaturalIntelligence/fast-xml-parser/commit/943ef0eb1b2d3284e72dd74f44a042ee9f07026e, https://github.com/NaturalIntelligence/fast-xml-parser/commit/ddcd0acf26ddd682cb0dc15a2bd6aa3b96bb1e69

Severity

9.3

CVSS Score
0
10

Basic Information

Ecosystem
Base CVSS
9.3
EPSS Probability
0.0002%
EPSS Percentile
0.05592%
Introduced Version
2f7d138af8338aaf65c1d98902f76259c7233373,292fb784334043214e29fa60adbb5630a36f5768,0
Fix Available
fe9a85270122036ae22637167ce38a5f71b73a5f,d4eb6b4713a8d11e6730943392419040898ecbc0,7.0.6-r1,7.1.0-r0,9.3.0-r1,2.95.12-r11,2.95.12-r13,5.14.3-r7,43.48.3-r0,5.5.0-r5,5.5.0-r6

Fix Critical Vulnerabilities Instantly

Secure your app without upgrading.
Fix Without Upgrading