Prototype Pollution Vulnerability in Lagom WHMCS Template by Lagom
CVE-2026-4239

5.1MEDIUM

Key Information:

Vendor

Lagom

Status
Whmcs Template
Vendor
CVE Published:
16 March 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-4239?

A vulnerability in the Lagom WHMCS Template, specifically affecting versions up to 2.3.7, allows for unauthorized modification of object prototype attributes within the Datatables component. This security flaw can be exploited remotely, making it a significant concern for users. The vendor has been notified of this issue but has not provided a response, leaving users at risk. Prompt action to mitigate this vulnerability is recommended as the exploit has already been made public.

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Affected Version(s)

WHMCS Template 2.3.0

WHMCS Template 2.3.1

WHMCS Template 2.3.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-4239 - Proof of Concept

CVE-2026-4239 - Proof of Concept

References

https://vuldb.com/?id.351181
vdb-entry
https://vuldb.com/?ctiid.351181
signaturepermissions-required
https://vuldb.com/?submit.771350
third-party-advisory

CVSS V4

Score:
5.1
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

s4nnty (VulDB User)
VulDB
JSON
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