CVE-2024-26736 in Linux
Summary
by MITRE • 04/03/2024
In the Linux kernel, the following vulnerability has been resolved:
afs: Increase buffer size in afs_update_volume_status()
The max length of volume->vid value is 20 characters. So increase idbuf[] size up to 24 to avoid overflow.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
[DH: Actually, it's 20 + NUL, so increase it to 24 and use snprintf()]
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Analysis
by VulDB Data Team • 08/03/2025
The vulnerability CVE-2024-26736 represents a buffer overflow condition within the Linux kernel's Andrew File System (AFS) implementation that specifically affects the afs_update_volume_status() function. This issue manifests when processing volume identifiers that can potentially exceed the allocated buffer capacity, creating a scenario where malicious input could lead to memory corruption and system instability. The vulnerability was identified through systematic analysis by the Linux Verification Center, which employs automated verification tools to detect potential security flaws in kernel code. The AFS subsystem serves as a distributed file system implementation that requires careful handling of identifier values to maintain system integrity and prevent unauthorized access patterns.
The technical flaw stems from insufficient buffer sizing in the afs_update_volume_status() function where the idbuf[] array does not adequately accommodate the maximum possible volume identifier value. While the volume identifier (vid) can reach up to 20 characters in length, the original buffer allocation fails to account for the null termination character required for string operations, creating a potential overflow condition when the system processes volume status updates. This buffer management issue directly violates the principles of secure coding practices and represents a classic example of inadequate input validation and memory allocation. The vulnerability operates at the kernel level, meaning that exploitation could potentially lead to privilege escalation or system compromise, making it particularly concerning for production environments.
The operational impact of this vulnerability extends beyond simple buffer overflow concerns as it affects the stability and security of systems relying on AFS for file storage operations. When the system attempts to process volume identifiers that approach the maximum length, the insufficient buffer sizing can cause memory corruption that may result in system crashes, data loss, or potentially exploitable conditions. The vulnerability affects systems using the Andrew File System implementation within the Linux kernel, which is commonly found in enterprise environments where distributed file systems are utilized for shared storage solutions. The implications are particularly severe because kernel-level buffer overflows can provide attackers with opportunities to execute arbitrary code with elevated privileges, potentially compromising the entire system infrastructure.
Mitigation strategies for CVE-2024-26736 focus on ensuring proper buffer allocation and string handling within the affected kernel subsystem. The recommended fix involves increasing the idbuf[] buffer size from its previous allocation to 24 characters, which accounts for the maximum volume identifier length of 20 characters plus the required null terminator. This approach aligns with secure coding practices and follows the principle of least privilege in buffer management. Additionally, the implementation should utilize snprintf() functions to ensure proper string termination and prevent overflow conditions. Organizations should prioritize applying the relevant kernel updates that include this fix, while also implementing monitoring for anomalous volume identifier processing patterns. The vulnerability demonstrates the importance of thorough input validation and buffer sizing in kernel code, particularly in distributed file system implementations where identifier management is critical for system operation and security. This fix represents a standard defensive programming approach that aligns with common security guidelines and helps prevent similar issues in other kernel subsystems where similar buffer management patterns may exist.
This vulnerability classification corresponds to CWE-121, which addresses stack-based buffer overflow conditions, and may also relate to CWE-122 for heap-based buffer overflows when considering the memory allocation patterns. From an ATT&CK framework perspective, this vulnerability could enable privilege escalation techniques through kernel exploitation, potentially mapping to T1068 for local privilege escalation and T1547 for persistence mechanisms. The fix implemented addresses the root cause by ensuring proper buffer sizing and string handling, which aligns with defensive coding practices recommended by various security standards including those from the National Institute of Standards and Technology and the Open Web Application Security Project.