CVE-2021-42840Public exploitNetwork attack vector

Remote code execution via log filename

Published Oct 22, 2021 · Updated Aug 4, 2024

Remote code execution in SuiteCRM before 7.11.19 allows remote authenticated users to execute PHP through the system settings Log File Name setting. The logger_file_name value can point to an attacker-controlled PHP file under the web root because validation blocks only lowercase PHP extensions, allowing alternate-case extensions to bypass the check. Exploitation requires prior administrator account takeover and results in server-side code execution.

CVSS severity9.0
Critical
EPSS probability58.95%
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 SuiteCRM before 7.11.19 allows remote authenticated users to execute PHP through the system settings Log File Name setting. The logger_file_name value can point to an attacker-controlled PHP file under the web root because validation blocks only lowercase PHP extensions, allowing alternate-case extensions to bypass the check. Exploitation requires prior administrator account takeover and results in server-side code execution.

The record

CVE
CVE-2021-42840
Published
Oct 22, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 22, 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.0NVDAV:N/AC:L/Au:S/C:C/I:C/A:C
8.8NVDCVSS:3.1/AV:N/AC:L/PR:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1505.003Server Software Component: Web Shell

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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