CVE-2023-42669

Samba: "rpcecho" development server allows denial of service via sleep() call on ad dc

MEDIUM
6.5
CVSS Score
Published: November 6, 2023 at 06:57 AM UTC
Updated: June 17, 2026 at 06:24 AM UTC
8 products affected across 2 vendorsEnterprise LinuxEnterprise Linux EusSAMBA

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Severity
MEDIUM6.5
Exploit prediction
EPSS 2%
SSVC
No known exploit

Description

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Vendor states this is fixed in 0:4.15.5-111.el9_0 (unaffected)
Vendor states this is fixed in 0:4.15.5-13.el8_6 (unaffected)
Vendor states this is fixed in 0:4.17.5-104.el9_2 (unaffected)
Vendor states this is fixed in 0:4.17.5-4.el8_8 (unaffected)
Vendor states this is fixed in 0:4.18.6-101.el9_3 (unaffected)
Vendor states this is fixed in 0:4.18.6-2.el8_9 (unaffected)
Vendor states this is fixed in 6 (unknown)
Vendor states this is fixed in 7 (unknown)
Vendor states this is fixed in 3 (unknown)
4.0.0 ≤ v < 4.17.124.18.0 ≤ v < 4.18.84.19.0 ≤ v < 4.19.1
Affected range stops below 4.17.12, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.18.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.19.1, so it looks safe — our inference, not a vendor statement

References (11)

Vendor Advisoryx_refsource_REDHATThird Party Advisory
https://access.redhat.com/errata/RHSA-2023:6209
Vendor Advisoryx_refsource_REDHATThird Party Advisory
https://access.redhat.com/errata/RHSA-2023:6744
VDB Entryx_refsource_REDHATThird Party Advisory
https://access.redhat.com/security/cve/CVE-2023-42669

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMredhat
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400NVD-CWE-noinfo

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