CVE-2025-59089— Python-kdcproxy: remote dos via unbounded tcp upstream buffering

Python-kdcproxy: remote dos via unbounded tcp upstream buffering

If an attacker causes kdcproxy to connect to an attacker-controlled KDC server (e.g. through server-side request forgery), they can exploit the fact that kdcproxy does not enforce bounds on TCP response length to conduct a denial-of-service attack. While receiving the KDC's response, kdcproxy copies the entire buffered stream into a new buffer on each recv() call, even when the transfer is incomplete, causing excessive memory allocation and CPU usage. Additionally, kdcproxy accepts incoming response chunks as long as the received data length is not exactly equal to the length indicated in the response header, even when individual chunks or the total buffer exceed the maximum length of a Kerberos message. This allows an attacker to send unbounded data until the connection timeout is reached (approximately 12 seconds), exhausting server memory or CPU resources. Multiple concurrent requests can cause accept queue overflow, denying service to legitimate clients.

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

不加限制或调节的资源分配

kdcproxy 安全漏洞

kdcproxy是latchset开源的一个Python库 kdcproxy存在安全漏洞，该漏洞源于未强制执行TCP响应长度边界，可能导致拒绝服务攻击。

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