Red Hat Certificate System/Enterprise Linux ACME responder server-side request forgery

Summaryinfo

A vulnerability described as problematic has been identified in Red Hat Certificate System and Enterprise Linux. This affects an unknown function of the component ACME responder. Such manipulation leads to server-side request forgery. This vulnerability is listed as CVE-2026-18369. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Red Hat Certificate System and Enterprise Linux (unknown version). Affected by this issue is an unknown code block of the component ACME responder. The manipulation with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Impacted is confidentiality. CVE summarizes:

A flaw was found in Dogtag PKI's ACME responder where the HTTP-01 challenge validator accepts IP address literals as dns identifiers and follows HTTP redirects without validating that the target is a public address. An unauthenticated ACME account holder can exploit this to perform server-side request forgery (SSRF), making the Dogtag server send HTTP GET requests to internal network services. With the InMemory database backend, the response body of internal targets is disclosed to the attacker through the ACME challenge error.

The advisory is shared for download at access.redhat.com. This vulnerability is handled as CVE-2026-18369 since 07/30/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 07/30/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-51078). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Red Hat

Name

• Certificate System
• Enterprise Linux

License

• open-source

Website

• Vendor: https://www.redhat.com/

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Once again VulDB remains the best source for vulnerability data.

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