Cloudanix VulnDB

CVE-2025-59089

Medium · 5.9

CVSS

5.9

EPSS

0.6%

Published

Nov 12, 2025

CISA due date

—

The record

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.

Affected packages

Ecosystem Package Introduced Fixed
AlmaLinux:10 python3-kdcproxy 0 1.0.0-19.el10_1
AlmaLinux:8 bind-dyndb-ldap 0 11.6-6.module_el8.10.0+3980+d78e8e90
AlmaLinux:8 custodia 0 0.6.0-3.module_el8.6.0+2881+2f24dc92
AlmaLinux:8 ipa-client 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-client-common 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-client-epn 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-client-samba 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-common 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-healthcheck 0 0.12-6.module_el8.10.0+4036+84b152d9
AlmaLinux:8 ipa-healthcheck-core 0 0.12-6.module_el8.10.0+4036+84b152d9
AlmaLinux:8 ipa-python-compat 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-selinux 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-server 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-server-common 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-server-dns 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 ipa-server-trust-ad 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 opendnssec 0 2.1.7-2.module_el8.10.0+3980+d78e8e90
AlmaLinux:8 python3-custodia 0 0.6.0-3.module_el8.6.0+2881+2f24dc92
AlmaLinux:8 python3-ipaclient 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 python3-ipalib 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 python3-ipaserver 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 python3-ipatests 0 4.9.13-20.module_el8.10.0+4050+3b475c71
AlmaLinux:8 python3-jwcrypto 0 0.5.0-2.module_el8.10.0+3844+20e075e5
AlmaLinux:8 python3-kdcproxy 0 0.4-5.module_el8.10.0+4069+1d9eaa78.2
AlmaLinux:8 python3-pyusb 0 1.0.0-9.1.module_el8.7.0+3349+cfeff52e
AlmaLinux:8 python3-qrcode 0 5.3-1.module_el8.10.0+3942+63b39a46
AlmaLinux:8 python3-qrcode-core 0 5.3-1.module_el8.10.0+3942+63b39a46
AlmaLinux:8 python3-yubico 0 1.3.2-9.1.module_el8.7.0+3349+cfeff52e
AlmaLinux:8 slapi-nis 0 0.60.0-4.module_el8.10.0+3844+20e075e5.alma.1
AlmaLinux:8 softhsm 0 2.6.0-5.module_el8.6.0+2881+2f24dc92
AlmaLinux:8 softhsm 0 2.6.0-5.module_el8.6.0+3031+2f24dc92
AlmaLinux:8 softhsm-devel 0 2.6.0-5.module_el8.6.0+2881+2f24dc92
AlmaLinux:8 softhsm-devel 0 2.6.0-5.module_el8.6.0+3031+2f24dc92
AlmaLinux:9 python3-kdcproxy 0 1.0.0-9.el9_7

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