CVE-2021-32819

HIGH EXPLOITED IN THE WILD NUCLEI

squirrelly < 9.0.0 - Remote Code Execution via Express Render API

Title source: llm
STIX 2.1

Exploitation Summary

CVE-2021-32819 has been observed exploited in the wild (reported by VulnCheck KEV, InTheWild.io). EIP tracks 1 public exploit from researchers including Abady0x1. A Nuclei detection template is also available.

AI-analyzed exploit summary The exploit leverages SquirrellyJS template engine misconfiguration to inject malicious code via the 'defaultFilter' parameter, leading to remote code execution. It sends a crafted HTTP request with a reverse shell payload to the target application.

Description

Squirrelly is a template engine implemented in JavaScript that works out of the box with ExpressJS. Squirrelly mixes pure template data with engine configuration options through the Express render API. By overwriting internal configuration options remote code execution may be triggered in downstream applications. This issue is fixed in version 9.0.0. For complete details refer to the referenced GHSL-2021-023.

Exploits (1)

nomisec WORKING POC 10 stars
by Abady0x1 · remote
https://github.com/Abady0x1/CVE-2021-32819

The exploit leverages SquirrellyJS template engine misconfiguration to inject malicious code via the 'defaultFilter' parameter, leading to remote code execution. It sends a crafted HTTP request with a reverse shell payload to the target application.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Trivial
Reliability
Reliable
Target: SquirrellyJS v8.0.0 to v8.0.8
No auth needed
Prerequisites: Target application using vulnerable SquirrellyJS version · Network access to the target
devstral-2 · analyzed Feb 18, 2026 Full analysis →

Nuclei Templates (1)

Nodejs Squirrelly - Remote Code Execution
HIGHby pikpikcu

Scores

CVSS v3 8.0
EPSS 0.8962
EPSS Percentile 99.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

Details

VulnCheck KEV 2024-02-07
InTheWild.io 2021-04-18
CWE
CWE-200
Status published
Products (2)
npm/squirrelly 0 - 9.0.0npm
squirrelly/squirrelly 8.0.8
Published May 14, 2021
Tracked Since Feb 18, 2026