MinIO 2018-08-18/2025-12-20 S3 Select Feature nextSplit allocation of resources

Summaryinfo

A vulnerability was found in MinIO 2018-08-18/2025-12-20 and classified as problematic. Affected is the function nextSplit of the component S3 Select Feature. The manipulation results in allocation of resources. This vulnerability was named CVE-2026-39414. The attack may be performed from remote. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in MinIO 2018-08-18/2025-12-20. It has been classified as problematic. Affected is the function nextSplit of the component S3 Select Feature. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on availability. CVE summarizes:

MinIO is a high-performance object storage system. From RELEASE.2018-08-18T03-49-57Z to before RELEASE.2025-12-20T04-58-37Z, MinIO's S3 Select feature is vulnerable to memory exhaustion when processing CSV files containing lines longer than available memory. The CSV reader's nextSplit() function calls bufio.Reader.ReadBytes('\n') with no size limit, buffering the entire input in memory until a newline is found. A CSV file with no newline characters causes the entire contents to be read into a single allocation, leading to an OOM crash of the MinIO server process. This is exploitable by any authenticated user with s3:PutObject and s3:GetObject permissions. The attack is especially practical when combined with compression: a ~2 MB gzip-compressed CSV can decompress to gigabytes of data without newlines, allowing a small upload to cause large memory consumption on the server. However, compression is not required — a sufficiently large uncompressed CSV with no newlines triggers the same issue.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-39414 since 04/07/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version RELEASE.2025-12-20T04-58-37Z eliminates this vulnerability. Applying the patch 7c14cdb60e53dbfdad2be644dfb180cab19fffa7 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• MinIO

Version

• 2018-08-18
• 2025-12-20

License

• open-source

Website

• Product: https://github.com/minio/minio/

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Once again VulDB remains the best source for vulnerability data.

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