CVE-2025-59089 SUSE CVE security@suse.de SUSE Security Team SUSE CVE-2025-59089 Interim 1 1 2025-12-23T00:17:10Z current 2025-12-23T00:17:10Z 2025-12-23T00:17:10Z cve-database/bin/generate-cvrf-cve.pl 2020-12-27T01:00:00Z CVE-2025-59089 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. The CVRF data is provided by SUSE under the Creative Commons License 4.0 with Attribution (CC-BY-4.0). https://lists.suse.com/pipermail/suse-liberty-linux-updates/2025-November/002259.html E-Mail link for RHSA-2025:21138 https://www.suse.com/support/security/rating/ SUSE Security Ratings SUSE Liberty Linux 9 python3-kdcproxy-1.0.0-9.el9_6 python3-kdcproxy-1.0.0-9.el9_6 as a component of SUSE Liberty Linux 9 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. CVE-2025-59089 SUSE Liberty Linux 9:python3-kdcproxy-1.0.0-9.el9_6 moderate