VDB-236367 · CVE-2023-39976 · EUVD-2023-43669

Clusterlabs libqb up to 2.0.7 Log Message log_blackbox.c buffer overflow

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.5	$0-$5k	0.00

Summaryinfo

A vulnerability was found in Clusterlabs libqb up to 2.0.7. It has been classified as critical. Affected is an unknown function of the file log_blackbox.c of the component Log Message Handler. Performing a manipulation results in buffer overflow. This vulnerability is reported as CVE-2023-39976. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical has been found in Clusterlabs libqb up to 2.0.7. This affects an unknown code block of the file log_blackbox.c of the component Log Message Handler. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

log_blackbox.c in libqb before 2.0.8 allows a buffer overflow via long log messages because the header size is not considered.

The weakness was disclosed 08/08/2023. It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2023-39976 since 08/08/2023. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 242806 (NewStart CGSL MAIN 7.02 : libqb Vulnerability (NS-SA-2025-0161)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.0.8 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 1bbaa929b77113532785c408dd1b41cd0521ffc8 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (242806) and EUVD (EUVD-2023-43669). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

Clusterlabs

Name

libqb

Version

License

open-source

Website

Product: https://github.com/ClusterLabs/libqb/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.6
VulDB Meta Temp Score: 7.6

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 242806
Nessus Name: NewStart CGSL MAIN 7.02 : libqb Vulnerability (NS-SA-2025-0161)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: libqb 2.0.8
Patch: 1bbaa929b77113532785c408dd1b41cd0521ffc8

Timelineinfo

08/08/2023 🔍
08/08/2023 +0 days 🔍
08/08/2023 +0 days 🔍
01/26/2026 +902 days 🔍

Sourcesinfo

Product: github.com

Advisory: 1bbaa929b77113532785c408dd1b41cd0521ffc8
Status: Confirmed

CVE: CVE-2023-39976 (🔍)
GCVE (CVE): GCVE-0-2023-39976
GCVE (VulDB): GCVE-100-236367
EUVD: 🔍

Entryinfo

Created: 08/08/2023 08:48
Updated: 01/26/2026 13:49
Changes: 08/08/2023 08:48 (44), 09/01/2023 08:04 (1), 09/01/2023 08:10 (12), 07/26/2025 06:23 (17), 01/26/2026 13:49 (1)
Complete: 🔍
Cache ID: 216::103