CVE-2023-42669: Red Hat Enterprise Linux

Medium severity, CVSS 6.5. EPSS: 1.7% chance of exploitation in the next 30 days.

A vulnerability was found in Samba's "rpcecho" development server, a non-Windows RPC server used to test Samba's DCE/RPC stack elements. This vulnerability stems from an RPC function that can be blocked indefinitely. The issue arises because the "rpcecho" service operates with only one worker in the main RPC task, allowing calls to the "rpcecho" server to be blocked for a specified time, causing service disruptions. This disruption is triggered by a "sleep()" call in the "dcesrv_echo_TestSleep()" function under specific conditions. Authenticated users or attackers can exploit this vulnerability to make calls to the "rpcecho" server, requesting it to block for a specified duration, effectively disrupting most services and leading to a complete denial of service on the AD DC. The DoS affects all other services as "rpcecho" runs in the main RPC task.

Affected products

• Red Hat Enterprise Linux: version 8.0 only; version 9.0 only
• Red Hat Enterprise Linux Eus: version 9.0 only
• Red Hat Enterprise Linux For IBM Z Systems: version 9.0_s390x only
• Red Hat Enterprise Linux For IBM Z Systems Eus: version 9.0_s390x only
• Red Hat Enterprise Linux For Power Little Endian: version 9.0_ppc64le only
• Red Hat Enterprise Linux For Power Little Endian Eus: version 9.0_ppc64le only
• Red Hat Storage: version 3.0 only
• Samba Samba: from 4.0.0, before 4.17.12 (fixed in 4.17.12); from 4.18.0, before 4.18.8 (fixed in 4.18.8); from 4.19.0, before 4.19.1 (fixed in 4.19.1)

Published 2023-11-06. Last modified 2026-06-17.