CVE-2021-3317

HIGH

klog_server < 2.4.1 - Authenticated OS Command Injection via async.php Source Parameter

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2021-3317. PoCs published by Metin Yunus Kandemir, Al1ex.

AI-analyzed exploit summary This exploit demonstrates an authenticated command injection vulnerability in Klog Server 2.4.1 via the 'source' parameter in async.php, executed through shell_exec() without input validation.

Description

KLog Server through 2.4.1 allows authenticated command injection. async.php calls shell_exec() on the original value of the source parameter.

Exploits (2)

exploitdb WORKING POC
by Metin Yunus Kandemir · pythonwebappsphp
https://www.exploit-db.com/exploits/49511

This exploit demonstrates an authenticated command injection vulnerability in Klog Server 2.4.1 via the 'source' parameter in async.php, executed through shell_exec() without input validation.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Trivial
Reliability
Reliable
Target: Klog Server 2.4.1
Auth required
Prerequisites: Valid credentials for Klog Server · Network access to the target
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 2 stars
by Al1ex · poc
https://github.com/Al1ex/CVE-2021-3317

This repository contains a functional Python exploit for CVE-2021-3317, an authenticated command injection vulnerability in Klog Server 2.4.1. The exploit leverages improper input validation in the 'source' parameter of async.php, allowing arbitrary command execution via shell_exec().

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Trivial
Reliability
Reliable
Target: Klog Server <= 2.4.1
Auth required
Prerequisites: Valid credentials for Klog Server · Network access to the target
devstral-2 · analyzed Feb 18, 2026 Full analysis →

References (2)

Core 2
Core References

Scores

CVSS v3 8.8
EPSS 0.4139
EPSS Percentile 98.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-78
Status published
Products (1)
klogserver/klog_server < 2.4.1
Published Jan 26, 2021
Tracked Since Feb 18, 2026