HOMEVULNERABILITIESCVE-2021-42643
HIGH

CVE-2021-42643

CWE-22Published: May 17, 2022· Updated: Jun 17, 2026

8.8
CVSS v3.1

Official Description

cmseasy V7.7.5_20211012 is affected by an arbitrary file write vulnerability. Through this vulnerability, a PHP script file is written to the website server, and accessing this file can lead to a code execution vulnerability.

NVD Source

Technical Analysis

CVE-2021-42643 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

cmseasy1 product(s)
cmseasy
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://jdr2021.github.io/2021/10/14/CmsEasy_7.7.5_20211012%E5%AD%98%E5%9C%A8%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E5%86%99%E5%85%A5%E5%92%8C%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E8%AF%BB%E5%8F%96%E6%BC%8F%E6%B4%9E/
ADVISORYhttps://jdr2021.github.io/2021/10/14/CmsEasy_7.7.5_20211012%E5%AD%98%E5%9C%A8%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E5%86%99%E5%85%A5%E5%92%8C%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E8%AF%BB%E5%8F%96%E6%BC%8F%E6%B4%9E/

All References (2)

→
https://jdr2021.github.io/2021/10/14/CmsEasy_7.7.5_20211012%E5%AD%98%E5%9C%A8%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E5%86%99%E5%85%A5%E5%92%8C%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E8%AF%BB%E5%8F%96%E6%BC%8F%E6%B4%9E/Exploit · Third Party Advisory
→
https://jdr2021.github.io/2021/10/14/CmsEasy_7.7.5_20211012%E5%AD%98%E5%9C%A8%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E5%86%99%E5%85%A5%E5%92%8C%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E8%AF%BB%E5%8F%96%E6%BC%8F%E6%B4%9E/Exploit · Third Party Advisory

Quick Facts

CVE IDCVE-2021-42643
CVSS Score8.8 / 10
SeverityHIGH
WeaknessCWE-22
CISA KEVNo
Affected1 vendor(s)
PublishedMay 17, 2022

Related CVEs (CWE-22)

CVE-2025-54261
10.0
CVE-2008-0405
10.0
CVE-2006-5487
10.0
CVE-2025-9118
10.0
CVE-2026-54917
10.0
CVE-2008-2241
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-42643 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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