CVE-2026-34968 in Adminer
Summary
by MITRE • 08/25/2026
Adminer before 5.4.3 contains an arbitrary file deletion vulnerability in SQLite mode where the database-list drop action fails to validate file extensions before deletion. An authenticated attacker can submit arbitrary relative file paths in the db[] parameter to delete any files writable by the PHP process.
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Analysis
by VulDB Data Team • 08/25/2026
The security flaw identified in Adminer versions prior to 5.4.3 represents a critical server-side request forgery and unauthorized access issue, specifically categorized under CWE-22 for Improper Limitation of a Pathname to a Restricted Directory and CWE-78 for OS Command Injection variants involving file system operations. This vulnerability arises from an insufficient validation mechanism within the application's SQLite database management module. When an authenticated user interacts with the interface to drop or delete a database, the backend logic processes the request by accepting input via the db[] parameter without adequately sanitizing relative file paths provided by the client. In standard web applications, such parameters are typically expected to contain only valid database names consisting of alphanumeric characters and safe symbols. However, in this specific implementation for SQLite mode, the application fails to enforce strict constraints on the format or location of these identifiers before passing them to underlying operating system functions responsible for file deletion.
The technical consequence of this lack of input validation is that an attacker who has obtained valid credentials can manipulate the db[] parameter to include directory traversal sequences such as dot-dot-slash characters. By constructing a malicious payload, the attacker can redirect the file deletion operation away from the intended SQLite database files and target arbitrary locations within the server's filesystem. The scope of this impact is strictly limited by the permissions granted to the PHP process running Adminer. If the web service operates with elevated privileges or has write access to sensitive directories such as configuration folders, log storage areas, or application root directories, an attacker can leverage this flaw to delete critical system files. This capability effectively allows for a denial of service attack against the hosting environment and potentially facilitates further exploitation by removing security controls or audit logs that might detect subsequent malicious activities.
From an operational perspective, this vulnerability undermines the integrity and availability guarantees provided by the web application infrastructure. While Adminer requires authentication to exploit, many deployments may suffer from weak credential policies, default passwords, or exposed administrative interfaces on public networks. Once authenticated access is achieved, the ability to delete arbitrary files transforms a simple database management tool into a potent weapon for system compromise. The attacker can disrupt service availability by deleting essential application components or configuration files required for startup and runtime stability. Furthermore, in environments where multiple applications share file systems or storage volumes, this flaw could lead to collateral damage affecting other services hosted on the same server, thereby expanding the blast radius of the initial breach beyond the Adminer instance itself.
Mitigation strategies must focus immediately on restricting input validation at the application layer and hardening the execution environment. The primary remediation is to upgrade Adminer to version 5.4.3 or later, where this specific validation logic has been corrected to ensure that only valid database names are processed during drop operations. For organizations unable to patch immediately due to compatibility constraints, a temporary workaround involves implementing strict input filtering rules on the web server or application firewall level to reject any requests containing relative path traversal sequences in parameters associated with file system modifications. Additionally, adhering to the principle of least privilege is essential; administrators should configure the PHP process running Adminer to operate within a restricted environment with minimal write permissions, ensuring that even if an attacker exploits this flaw, they cannot access or delete files outside of designated temporary directories. Regular audits of user accounts and enforcement of strong authentication policies further reduce the attack surface by preventing unauthorized actors from reaching the vulnerable functionality in the first place.