CVE-2026-4239: Lagom WHMCS Template Datatables prototype pollution

Severity: low (CVSS 3.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-16 · updated 2026-06-17
Weakness: CWE-94

Description

A vulnerability was found in Lagom WHMCS Template up to 2.3.7. Impacted is an unknown function of the component Datatables. The manipulation results in improperly controlled modification of object prototype attributes. It is possible to launch the attack remotely. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.

Affected products

Lagom WHMCS Template: 2.3.0, 2.3.1, 2.3.2, 2.3.3, 2.3.4, 2.3.5 (+2)

References

https://github.com/devsamuelsantiago/lagom-prototype-pollution-poc/
https://github.com/devsamuelsantiago/lagom-prototype-pollution-poc/blob/main/lagom-prototype-pollution-poc.js
https://vuldb.com/?ctiid.351181
https://vuldb.com/?id.351181
https://vuldb.com/?submit.771350

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