CVE-2021-40097Network attack vector

Authenticated code execution via traversed upload filename

Published Sep 27, 2021 · Updated Aug 4, 2024

Path traversal in Concrete CMS 8.5.5 and earlier allows remote authenticated users to execute uploaded PHP code through bFilename. The upload handler accepts directory traversal sequences in the bFilename parameter and writes an uploaded PHP file outside the intended directory. A valid CMS account and access to the affected upload path are required; successful exploitation runs attacker-supplied code on the web server.

CVSS severity8.8
High
EPSS probability2.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Concrete CMS 8.5.5 and earlier allows remote authenticated users to execute uploaded PHP code through bFilename. The upload handler accepts directory traversal sequences in the bFilename parameter and writes an uploaded PHP file outside the intended directory. A valid CMS account and access to the affected upload path are required; successful exploitation runs attacker-supplied code on the web server.

The record

CVE
CVE-2021-40097
Published
Sep 27, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1190, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 27, 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

8.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5NIST National Vulnerability DatabaseAV:N/AC:L/Au:S/C:P/I:P/A:P

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application
T1505.003Server Software Component: Web Shell

Public exploit references

No public exploit references are available in this record.

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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