Zeroshell - RCE (CVE-2020-29390)
199Exploiting IPs reported
Zeroshell 3.9.3 contains a command injection vulnerability in the /cgi-bin/kerbynet StartSessionSubmit parameter that could allow an unauthenticated attacker to execute a system command by using shell metacharacters and the %0a character.
CrowdSec analysis
CVE-2020-29390 is a critical vulnerability in Zeroshell that enables unauthenticated remote code execution via command injection within the CGI interface.
CrowdSec has been tracking this vulnerability and its exploits since 26th of May 2025.
According to CrowdSec data, while opportunistic exploitation dominates, a portion of threat actors trying to exploit CVE-2020-29390 apply basic targeting methods such as port or service detection. This indicates emerging patterns of selective targeting. In addition, according to the CrowdSec network, attack volume against CVE-2020-29390 has dipped slightly compared to the previous week. Although still commonly targeted, the decline suggests a cooling-off period. Long-term relevance remains, but attention is waning.
Observed exploitation activity typically targets URLs containing /cgi-bin/kerbynet.
Exploitation
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Common Weakness Enumeration (CWE)
Protection
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Blocklist
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