CVE-2026-116828 in YesWiki
Summary
by MITRE • 10/27/2026
YesWiki before 4.7.0 contains a sql injection vulnerability in despam.php where the from parameter is escaped but placed in an unquoted INTERVAL position. Authenticated administrators can inject SQL via the from POST parameter to perform blind reads of the database including user password hashes.
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Analysis
by VulDB Data Team • 10/27/2026
The vulnerability identified in YesWiki versions prior to 4.7.0 represents a critical security flaw within the application's administrative interface, specifically located in the despam.php module. This component is designed to manage spam filtering and moderation tasks for wiki content. The core technical issue stems from improper input validation and sanitization mechanisms applied to the from parameter submitted via POST requests. Although the developers implemented an escaping function intended to neutralize malicious SQL characters, this mitigation was insufficient because it failed to account for the specific syntactic context in which the variable is utilized within the database query structure.
The technical flaw arises from the placement of the escaped input into an unquoted INTERVAL position within a MySQL statement. In standard SQL syntax, string literals must be enclosed in quotes to distinguish them as text data types. However, when a value is intended for use with interval arithmetic or date manipulation functions that expect numeric or specific time-unit formats, developers often omit surrounding quotes. The vulnerability occurs because the escaping logic treats all inputs uniformly without considering this contextual difference. Consequently, an attacker can inject SQL code that bypasses the escape filters by exploiting how MySQL parses unquoted values in interval expressions. This allows for blind SQL injection attacks where the injected payload is executed as part of the query's logical structure rather than being treated merely as data.
The operational impact of this vulnerability is severe due to its potential for unauthorized data access and manipulation. Because YesWiki requires authentication, only authenticated administrators can exploit this flaw. However, given that administrative accounts often possess elevated privileges within the application ecosystem, an attacker with such credentials can leverage this SQL injection to perform blind reads against the underlying database. This capability enables the extraction of sensitive information including user password hashes, session tokens, and other confidential wiki data. The ability to extract password hashes is particularly dangerous as it facilitates offline brute-force attacks, potentially leading to credential compromise across multiple systems if users employ reused passwords.
From a classification perspective, this vulnerability aligns with CWE-89, which covers Improper Neutralization of Special Elements used in an SQL Command, commonly known as SQL Injection. The specific nature of the flaw, where input is placed in an unquoted context leading to execution, also relates to CWE-643 regarding improper handling of unexpected data types. In terms of adversary tactics and techniques, this exploitation vector corresponds to ATT&CK technique T1059, specifically sub-technique 007 for Command Line Interface usage if the injection leads to command execution, or more accurately T1190 Exploit Public-Facing Application combined with T1005 Data from Local System. The blind nature of the read suggests potential alignment with T1048 Exfiltration Over Alternative Protocol if data is exfiltrated through DNS or HTTP channels constructed via SQL injection payloads.
Mitigation strategies for this vulnerability involve immediate patching to version 4.7.0 or later, where the developers have addressed the input validation logic in despam.php. For organizations unable to upgrade immediately, a temporary workaround involves restricting access to the administrative interface using network-level controls such as firewalls or IP whitelisting to limit exposure to trusted internal networks only. Additionally, implementing Web Application Firewalls with rules specifically tuned for SQL injection patterns can provide an additional layer of defense by blocking suspicious POST requests containing interval-related syntax anomalies. Long-term remediation should include adopting parameterized queries prepared statements which inherently separate code from data, thereby eliminating the possibility of context-based injection regardless of how input is escaped or quoted. Regular security audits and static application security testing focused on database interaction layers are recommended to prevent similar contextual vulnerabilities in future development cycles.