CVE-2021-47936

CRITICAL

OpenCATS 0.9.4 Remote Code Execution via Resume Upload

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-47936. PoCs published by Nicholas Ferreira.

AI-analyzed exploit summary This script exploits a file upload vulnerability in OpenCATS 0.9.4 to achieve remote code execution by uploading a malicious PHP file disguised as a GIF. It automates the process of identifying active job postings, uploading the payload, and establishing a reverse shell.

Description

OpenCATS 0.9.4 contains a remote code execution vulnerability that allows unauthenticated attackers to execute arbitrary commands by uploading malicious PHP files disguised as resume attachments. Attackers can upload PHP payloads through the careers job application endpoint and execute system commands via POST requests to the uploaded file in the upload directory.

Exploits (1)

exploitdb WORKING POC
by Nicholas Ferreira · bashwebappsphp
https://www.exploit-db.com/exploits/50585

This script exploits a file upload vulnerability in OpenCATS 0.9.4 to achieve remote code execution by uploading a malicious PHP file disguised as a GIF. It automates the process of identifying active job postings, uploading the payload, and establishing a reverse shell.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: OpenCATS <=0.9.4 Countach
No auth needed
Prerequisites: active job postings on the target OpenCATS instance
devstral-2 · analyzed May 10, 2026 Full analysis →

References (4)

Core 4
Core References
Exploit exploit
ExploitDB-50585
https://www.exploit-db.com/exploits/50585
Product product
Official Product Homepage
https://www.opencats.org/
Product product
Product Reference
https://github.com/opencats/OpenCATS
Third Party Advisory third-party-advisory
VulnCheck Advisory: OpenCATS 0.9.4 Remote Code Execution via Resume Upload
https://www.vulncheck.com/advisories/opencats-remote-code-execution-via-resume-upload

Scores

CVSS v3 9.8
EPSS 0.0032
EPSS Percentile 55.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact total

Details

CWE
CWE-306
Status published
Products (1)
Opencats/OpenCATS < 0.9.4
Published May 10, 2026
Tracked Since May 10, 2026