CVE-2026-107821 in MariaDB
Summary
by MITRE • 10/09/2026
MariaDB server is a community developed fork of MySQL server. From 10.6.1 until 10.6.28, 10.11.19, 11.4.13, 11.8.9, 12.3.3, and 13.0.2, MariaDB insufficiently validated counts, offsets, lengths, and field boundaries in FRM metadata while opening binary FRM files. An attacker able to place a crafted FRM file in the data directory could trigger out-of-bounds reads or writes, crash the server, or potentially execute code. This issue is fixed in versions 10.6.28, 10.11.19, 11.4.13, 11.8.9, 12.3.3, and 13.0.2.
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Analysis
by VulDB Data Team • 10/09/2026
MariaDB is a widely deployed relational database management system that serves as a community-developed fork of the MySQL server, offering enhanced features and performance optimizations for enterprise workloads. The vulnerability described pertains to a critical flaw in how MariaDB processes binary FRM files, which are metadata files used by the storage engine to define table structures such as column definitions, indexes, and data types. These files are essential for the database server to understand the schema of stored tables during query execution and administrative operations. The issue affects multiple long-term support and current release branches, specifically versions 10.6 through 10.6.28, 10.11 through 10.11.19, 11.4 through 11.4.13, 11.8 through 11.8.9, 12.3 through 12.3.3, and 13.0 up to version 13.0.2. This broad impact across versions indicates a systemic weakness in the core file parsing logic rather than an isolated incident in a single release cycle.
The technical root cause of this vulnerability lies in insufficient validation of input parameters derived from FRM metadata files, specifically concerning counts, offsets, lengths, and field boundaries. When MariaDB opens a binary FRM file to load table structure information into memory, it relies on the integrity of data contained within that file. The flaw allows an attacker who can place a crafted or maliciously constructed FRM file into the server's data directory to exploit these validation gaps. Because the software fails to rigorously check whether the values read from the metadata align with actual buffer sizes and array limits, it proceeds to perform memory operations based on untrusted input. This lack of boundary checking is a classic example of improper input validation that leads to memory corruption issues.
The operational impact of this vulnerability is severe due to its potential for remote code execution or denial of service. An attacker capable of uploading a malicious FRM file, potentially through an SQL injection vector if the database allows direct file system access via functions like LOAD_FILE or SELECT INTO OUTFILE, can trigger out-of-bounds reads or writes in the server's memory space. Out-of-bounds reads may lead to information disclosure by leaking sensitive data from adjacent memory regions, such as authentication credentials or internal application logic. More critically, out-of-bounds writes can corrupt heap structures, allowing an attacker to overwrite function pointers or return addresses. This capability enables arbitrary code execution with the privileges of the MariaDB server process, effectively granting full control over the underlying operating system if the database is running with elevated permissions. Additionally, even without successful exploitation for code execution, the vulnerability can cause the server to crash unpredictably, resulting in a denial of service that disrupts availability for all connected clients and applications relying on the database.
From a threat modeling perspective, this vulnerability aligns with Common Weakness Enumeration (CWE) categories such as CWE-125 Out-of-bounds Read and CWE-787 Out-of-bounds Write, which describe memory safety violations resulting from improper boundary checks. In terms of attack tactics, it relates to MITRE ATT&CK techniques involving initial access via SQL injection or file upload if the attacker has a foothold within the application layer, followed by privilege escalation through exploitation of the database engine itself. The ability to execute code remotely makes this a high-severity issue that requires immediate attention from security teams and database administrators.
Mitigation strategies primarily involve upgrading to patched versions immediately. Users running any affected version must upgrade to MariaDB 10.6.28, 10.11.19, 11.4.13, 11.8.9, 12.3.3, or 13.0.2 where the validation logic has been corrected to ensure that all metadata fields are strictly validated against expected bounds before memory operations are performed. In environments where immediate patching is not feasible due to compatibility testing requirements, administrators should implement strict access controls on the database server's file system to prevent unauthorized users or compromised application accounts from writing files into the MariaDB data directory. Furthermore, applying principle of least privilege by running the MariaDB service under a restricted user account with minimal filesystem permissions can reduce the impact if an exploit is attempted. Regular security audits and static code analysis tools should also be employed during development cycles to detect similar input validation flaws before they reach production environments.