CVE-2021-42342Public exploitNetwork attack vector

Remote code execution via unprefixed CGI variables

Published Oct 14, 2021 · Updated Aug 4, 2024

Remote code execution in Embedthis GoAhead 4.x and 5.x before 5.1.5 allows remote attackers to execute code through CGI file uploads. The file upload filter forwards attacker-controlled form variable names into the CGI process environment without adding the CGI_ prefix. Exploitation requires an enabled file upload filter and a reachable CGI program, and the injected environment can load attacker-supplied code in the server process.

CVSS severity9.8
Critical
EPSS probability59.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Embedthis GoAhead 4.x and 5.x before 5.1.5 allows remote attackers to execute code through CGI file uploads. The file upload filter forwards attacker-controlled form variable names into the CGI process environment without adding the CGI_ prefix. Exploitation requires an enabled file upload filter and a reachable CGI program, and the injected environment can load attacker-supplied code in the server process.

The record

CVE
CVE-2021-42342
Published
Oct 14, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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