CVE-2025-59089
Python-kdcproxy: remote dos via unbounded tcp upstream buffering
Description
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.
INFO
Published Date :
Nov. 12, 2025, 5:15 p.m.
Last Modified :
Nov. 20, 2025, 10:15 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2025-59089
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Enforce bounds on TCP response length.
- Sanitize KDC proxy inputs to prevent SSRF.
- Implement robust error handling for network data.
- Monitor server memory and CPU usage.
Public PoC/Exploit Available at Github
CVE-2025-59089 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-59089.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-59089 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-59089
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Contains information on all of the CVEs I found.
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-59089 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-59089 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
Nov. 20, 2025
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2025:21806 Added Reference https://access.redhat.com/errata/RHSA-2025:21818 Added Reference https://access.redhat.com/errata/RHSA-2025:21819 Added Reference https://access.redhat.com/errata/RHSA-2025:21820 Added Reference https://access.redhat.com/errata/RHSA-2025:21821 -
CVE Modified by [email protected]
Nov. 19, 2025
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2025:21748 -
CVE Modified by [email protected]
Nov. 17, 2025
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2025:21448 -
CVE Modified by [email protected]
Nov. 12, 2025
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2025:21138 Added Reference https://access.redhat.com/errata/RHSA-2025:21139 Added Reference https://access.redhat.com/errata/RHSA-2025:21140 Added Reference https://access.redhat.com/errata/RHSA-2025:21141 Added Reference https://access.redhat.com/errata/RHSA-2025:21142 -
New CVE Received by [email protected]
Nov. 12, 2025
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-770 Added Reference https://access.redhat.com/security/cve/CVE-2025-59089 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2393958 Added Reference https://github.com/latchset/kdcproxy/pull/68