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-2026-26278

fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)
Back to all
CVE

CVE-2026-26278

fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)

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. In versions 4.1.3 through 5.3.5, the XML parser can be forced to do an unlimited amount of entity expansion. With a very small XML input, it’s possible to make the parser spend seconds or even minutes processing a single request, effectively freezing the application. Version 5.3.6 fixes the issue. As a workaround, avoid using DOCTYPE parsing by processEntities: false option.

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
7.5
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
C
H
U
7.5
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Related Resources

No items found.

References

https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.3.6, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26278.json, https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-jmr7-xgp7-cmfj, https://nvd.nist.gov/vuln/detail/CVE-2026-26278, https://github.com/NaturalIntelligence/fast-xml-parser/commit/910dae5be2de2955e968558fadf6e8f74f117a77

Severity

7.5

CVSS Score
0
10

Basic Information

Ecosystem
Base CVSS
7.5
EPSS Probability
0.00032%
EPSS Percentile
0.09194%
Introduced Version
2f7d138af8338aaf65c1d98902f76259c7233373,292fb784334043214e29fa60adbb5630a36f5768,0
Fix Available
ecb2ca118ad3d6c62f2cc90416b58da24db5d18b,d4eb6b4713a8d11e6730943392419040898ecbc0,7.0.6-r1,7.1.0-r0,2.11.0-r15,8.17.10-r10,8.19.11-r1,9.0.8-r10,9.1.10-r5,9.2.5-r3,9.3.0-r1,2.15.0-r12,2.95.12-r11,2.95.12-r13,0.8.2-r3,5.14.3-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