CVE-2026-44583: Paymenter is a free and open-source webshop solution for management of hosting services. In versions prior to 1.5.0, the PayPal webhook endpoint /exte...

Description

Paymenter is a free and open-source webshop solution for management of hosting services. In versions prior to 1.5.0, the PayPal webhook endpoint /extensions/paypal/webhook processes the PAYPAL-CERT-URL HTTP header without validation, allowing attackers to control server-side HTTP request destinations. This value is passed directly into a server-side HTTP request via file_get_contents, allowing attackers to control the destination of the request. No allowlist, validation, or signature verification is applied to the header before usage. As a result, the application can be coerced into performing HTTP requests to attacker-controlled or internal network destinations. This vulnerability allows remote unauthenticated attackers to induce server-side HTTP GET requests to arbitrary external or internal endpoints. Depending on network configuration, this may lead to: blind SSRF to external attacker-controlled systems, and potential access to internal network services No direct response data is returned to the attacker (blind SSRF), but the issue may still enable sensitive network probing or data exfiltration via side channels. This issue has been fixed in version 1.5.0.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

0.41%

34.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-918

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Paymenter	Paymenter	< 1.5.0

References

https://github.com/Paymenter/Paymenter/security/advisories/GHSA-7wwh-xcc3-9fcg

Timeline

Published: Jul 20, 2026
Last Modified: Jul 23, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-44583?

Paymenter is a free and open-source webshop solution for management of hosting services. In versions prior to 1.5.0, the PayPal webhook endpoint /extensions/paypal/webhook processes the PAYPAL-CERT-URL HTTP header without validation, allowing attackers to control server-side HTTP request destinations. This value is passed directly into a server-side HTTP request via file_get_contents, allowing attackers to control the destination of the request. No allowlist, validation, or signature verification is applied to the header before usage. As a result, the application can be coerced into performing HTTP requests to attacker-controlled or internal network destinations. This vulnerability allows remote unauthenticated attackers to induce server-side HTTP GET requests to arbitrary external or internal endpoints. Depending on network configuration, this may lead to: blind SSRF to external attacker-controlled systems, and potential access to internal network services No direct response data is returned to the attacker (blind SSRF), but the issue may still enable sensitive network probing or data exfiltration via side channels. This issue has been fixed in version 1.5.0.

How severe is CVE-2026-44583?

CVE-2026-44583 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.41% probability of exploitation in the next 30 days.

How do I fix CVE-2026-44583?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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