CVE-2026-39879 in syslog-ng
Summary
by MITRE • 07/20/2026
Due to a missing sanitization call in [`afsql_dd_run_query`](https://github.com/syslog-ng/syslog-ng/blob/649e6e18e3459fb4467000a88dfb12fa97f9719c/modules/afsql/afsql.c#L219), syslog-ng before 4.12 are vulnerable to SQL injection from an untrusted source. This is not part of the default configuration, the SQL driver has to be manually configured.
Fixes are in syslog-ng 4.12, syslog-ng Premium Edition 8.2 and syslog-ng Store Box 7.8
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Analysis
by VulDB Data Team • 07/20/2026
The vulnerability identified in syslog-ng versions prior to 4.12 represents a critical SQL injection flaw that stems from inadequate input sanitization within the afsql_dd_run_query function. This weakness exists specifically within the afsql module which handles database operations for syslog-ng, creating an attack vector where malicious actors can inject arbitrary SQL commands through improperly validated inputs. The vulnerability requires manual configuration of the SQL driver to become exploitable, meaning it does not affect default installations but poses significant risk when administrators enable database logging functionality.
The technical implementation flaw occurs at line 219 in the afsql.c source file where the afsql_dd_run_query function fails to properly sanitize user-provided data before incorporating it into SQL query construction. This missing sanitization call allows attackers who can influence log data processing to craft malicious inputs that get directly embedded into database queries without proper escaping or parameterization. The vulnerability specifically affects the database driver functionality and operates at the data processing layer where syslog-ng transforms log messages into structured database entries, making it particularly dangerous in environments where untrusted log sources are processed.
The operational impact of this vulnerability extends beyond simple data compromise, as successful exploitation could enable attackers to execute arbitrary database commands with the privileges of the syslog-ng process. This risk is particularly elevated when considering that syslog-ng often runs with elevated permissions to access system logs and database resources. Attackers could potentially extract sensitive information from database tables, modify or delete log entries, or even escalate their privileges by leveraging database access to perform unauthorized operations. The vulnerability's manual configuration requirement does not diminish its severity, as it represents a latent security flaw that can be activated by any administrator who configures the afsql driver inappropriately.
Security mitigations for this vulnerability require immediate upgrade to syslog-ng 4.12 or equivalent versions of syslog-ng Premium Edition 8.2 and syslog-ng Store Box 7.8 where the sanitization function has been properly implemented. Organizations should also conduct comprehensive audits of their syslog-ng configurations to identify any instances where afsql drivers have been manually enabled, particularly in environments with untrusted log sources. The fix addresses the root cause by implementing proper input validation and sanitization procedures that prevent malicious SQL fragments from being incorporated into database queries. This aligns with established security practices outlined in cwe-89 for SQL injection prevention and represents a fundamental requirement for maintaining secure data processing pipelines.
The vulnerability demonstrates the importance of proper input validation in database access components, particularly in logging and monitoring systems where untrusted inputs are routinely processed. It highlights how seemingly isolated functionality can become a critical attack surface when proper security controls are omitted from code implementations. Organizations implementing similar logging solutions should consider the broader implications of database integrations and ensure that all data processing components follow established security guidelines for preventing injection attacks. This vulnerability serves as a reminder that even specialized security tools require rigorous input validation to prevent exploitation through indirect attack paths.
This flaw represents a significant departure from secure coding practices that should be implemented across all data processing modules in enterprise security solutions. The absence of sanitization in database query construction violates fundamental security principles and creates opportunities for attackers to leverage legitimate system functionality for malicious purposes. The vulnerability's classification under cwe-89 underscores its severity as a direct injection attack vector, while the attack surface mapping aligns with ATT&CK technique T1070.004 for data manipulation and T1566.002 for spearphishing with social engineering components that could be used to compromise system integrity.