python-kdcproxy Realm‑Controlled DNS SRV server-side request forgery

Summaryinfo

A vulnerability described as critical has been identified in python-kdcproxy. This issue affects some unknown processing of the component Realm‑Controlled DNS SRV Handler. Such manipulation leads to server-side request forgery. This vulnerability is traded as CVE-2025-59088. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in python-kdcproxy (unknown version) and classified as critical. Affected by this issue is an unknown code block of the component Realm‑Controlled DNS SRV Handler. 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, integrity, and availability. CVE summarizes:

If kdcproxy receives a request for a realm which does not have server addresses defined in its configuration, by default, it will query SRV records in the DNS zone matching the requested realm name. This creates a server-side request forgery vulnerability, since an attacker could send a request for a realm matching a DNS zone where they created SRV records pointing to arbitrary ports and hostnames (which may resolve to loopback or internal IP addresses). This vulnerability can be exploited to probe internal network topology and firewall rules, perform port scanning, and exfiltrate data. Deployments where the "use_dns" setting is explicitly set to false are not affected.

The advisory is shared for download at bugzilla.redhat.com. This vulnerability is handled as CVE-2025-59088. 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 $0-$5k (estimation calculated on 11/21/2025).

The vulnerability scanner Nessus provides a plugin with the ID 275245 (RHEL 9 : python-kdcproxy (RHSA-2025:21139)), which helps to determine the existence of the flaw in a target environment.

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 databases at Tenable (275245), EUVD (EUVD-2025-131921) and CERT Bund (WID-SEC-2025-2586). Once again VulDB remains the best source for vulnerability data.

Affected

• Red Hat Enterprise Linux
• Fedora Linux
• Oracle Linux

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Type

• Programming Language Software

Name

• python-kdcproxy

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• 🔒

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Once again VulDB remains the best source for vulnerability data.

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