Paymenter: URL parameter injection bypasses paid plan limits at checkout

published 2026-06-30 4 mo ago modified 2026-09-10 1 mo ago also GHSA-5q4q-834j-g8g4 , EUVD-2026-46096

cvss: 8.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits: 0; none known

Paymenter is a free and open-source webshop solution for management of hosting services. In versions prior to 1.5.1, the checkout component improperly filters URL-writable properties, allowing authenticated users to inject arbitrary key-value pairs into server provisioning parameters. Because bundled server extensions prioritize these user-supplied properties over administrator-defined configurations, a regular user can override hosting plans and resource limits at checkout without special privileges. The Checkout Livewire component's $checkoutConfig property exposed via URL query parameters, only validating keys explicitly defined by an extension's configuration method, allowing any undefined injected keys to bypass validation entirely. These unsanitized keys are then stored directly in the database by the cart component and later passed to server extensions during provisioning, enabling user-injected data to override intended administrator settings. Depending on the active extension, this leads to unauthorized overrides of core resource limits (such as CPU, RAM, storage, or package tiers). No administrative privileges are required to exploit this vulnerability. This issue has been fixed in version 1.5.1.

Patch / fix

fixed in 1

packagist paymenter/paymenter 1.5.1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 3 mo ago (2026-07-22)

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L
GitHub	3.1	8.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L

Affected packages

ecosystem	package	affected	fixed in
packagist	paymenter/paymenter	<1.5.1	1.5.1

Affected products

Paymenter Paymenter

Classification

Weakness

CWE-20 Improper Input Validation
CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary