CVE-2026-52763 in YesWiki
Summary
by MITRE • 09/05/2026
YesWiki is a wiki system written in PHP. Prior to version 4.6.6, the recentchanges action (actions/recentchanges.php) accepts a period argument from two disjoint parameter spaces. A whitelist validates only the URL form against ['day','week','month']. The action-argument form takes the else branch with no validation, and the value flows into PageManager::getRecentlyChanged(), where it is interpolated into a WHERE time >= '...' ORDER BY time DESC clause without escaping or parameterization. UNION-based injection succeeds, the leaked rows render into the response page, so any visitor of the trigger page sees the exfiltrated data. The vulnerability provides arbitrary read of the YesWiki database to anyone who can save the trigger page. On a default install (default_write_acl='*'), this includes anonymous users, subject to the hashcash JS check on the page-edit form. Once the trigger page is saved, every subsequent view fires the injection as the SQLi is stored. Stored SQL injection is reachable through the page-edit flow, with arbitrary database read. This issue has been patched in version 4.6.6.
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Analysis
by VulDB Data Team • 09/05/2026
YesWiki is a wiki system implemented in PHP that allows users to create and edit collaborative web pages. A critical security flaw exists within the recentchanges action located at actions/recentchanges.php, which handles the display of recently modified content. This component suffers from an input validation bypass that leads to stored SQL injection vulnerabilities. The vulnerability arises because the action accepts a period argument derived from two distinct parameter spaces with inconsistent handling logic. Specifically, when the URL form is used, a whitelist validates the input against a restricted set of values including day, week, and month. However, when the action-argument form is utilized, the code follows an else branch that performs no validation whatsoever on the provided period value.
The unvalidated input flows directly into the PageManager::getRecentlyChanged() method without any sanitization or parameterization. Within this function, the raw user-supplied data is interpolated directly into a SQL query string formatted as WHERE time >= '...' ORDER BY time DESC. Because the input is not escaped, an attacker can inject arbitrary SQL commands using UNION-based techniques to manipulate the database query structure. This allows for the extraction of sensitive information from other tables within the YesWiki database schema, effectively granting unauthorized read access to the entire backend data store.
The impact of this vulnerability is severe due to its stored nature and potential reachability by unauthenticated users. Once an attacker saves a page containing the malicious payload via the page-edit flow, the injected SQL code becomes persistent in the database. Consequently, every subsequent user who views that specific trigger page will inadvertently execute the injection against their own session or the server's context depending on implementation details, resulting in data exfiltration visible within the response page rendered to them. On default installations where the write access control list is set to allow all users including anonymous ones, any visitor can save such a malicious page. While there may be client-side protections like hashcash JavaScript checks intended to prevent spam or abuse on the edit form, these are easily bypassed and do not constitute adequate security controls against SQL injection attacks.
This vulnerability aligns with CWE-89 Improper Neutralization of Special Elements used in an SQL Command as it involves the direct interpolation of user input into a database query without proper escaping. From a tactical perspective, this maps to ATT&CK technique T1059 Command and Scripting Interpreter for initial access via page editing and T1213 Data from Information Repositories for exfiltrating data through UNION-based injection. The persistence mechanism classifies it as stored SQLi rather than reflected or DOM-based variants, increasing its severity by allowing passive exploitation without requiring complex user interaction beyond viewing a compromised page.
To mitigate this risk, organizations running YesWiki must upgrade to version 4.6.6 or later where the validation logic has been corrected to apply consistent checks across all input paths and parameterize database queries properly. For systems that cannot immediately patch due to operational constraints, implementing strict server-side input validation on the recentchanges action parameters is essential. Additionally, deploying a Web Application Firewall with rules capable of detecting UNION-based SQL injection patterns can provide an additional layer of defense against exploitation attempts while administrative teams work toward full remediation.