CVE-2021-42643Public exploitNetwork attack vector

Authenticated code execution via template path traversal

Published May 17, 2022 · Updated Aug 4, 2024

Arbitrary file write in CmsEasy 7.7.5_20211012 allows remote authenticated users to execute PHP code through the template editor. In lib/admin/template_admin.php, the save action decodes traversal tokens in sid into ../ segments and passes the resulting path and scontent to file_put_contents without confining the destination. A valid back-end session is required; authenticated access permits placement of a PHP script in the web root and its execution through an HTTP request.

CVSS severity8.8
High
EPSS probability1.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary file write in CmsEasy 7.7.5_20211012 allows remote authenticated users to execute PHP code through the template editor. In lib/admin/template_admin.php, the save action decodes traversal tokens in sid into ../ segments and passes the resulting path and scontent to file_put_contents without confining the destination. A valid back-end session is required; authenticated access permits placement of a PHP script in the web root and its execution through an HTTP request.

The record

CVE
CVE-2021-42643
Published
May 17, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 17, 2022CVE 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 NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5NIST NVDAV: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 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-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1505.003Web 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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