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GHSA-h749-fxx7-pwpg

Fix: minio/minio#8200

GHSA-h749-fxx7-pwpg is a CWE-770 vulnerability in github.com/minio/minio. O3 Security confirms whether GHSA-h749-fxx7-pwpg is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

MinIO affected a DoS via Unbounded Memory Allocation in S3 Select CSV Parsing

Also known asBIT-minio-2026-39414CVE-2026-39414GO-2026-5415
Published
Apr 9, 2026
Updated
Jul 21, 2026
Affected
1 pkg
Patched
None yet
Exploits
None indexed
Exploitation data as of Jul 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
🐹github.com/minio/minio

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

What kind of vulnerability is it? Who is impacted?

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.

Affected component: internal/s3select/csv/reader.go, function nextSplit().

CWE: CWE-770 (Allocation of Resources Without Limits or Throttling)

Affected Versions

All MinIO releases are through the final release of the minio/minio open-source project.

The vulnerability was introduced in commit https://github.com/minio/minio/commit/7c14cdb60e53dbfdad2be644dfb180cab19fffa7, which added S3 Select support for CSV. The CSV reader has used unbounded line reads since this commit (originally via Go's stdlib encoding/csv.Reader, later via bufio.Reader.ReadBytes after a refactor in PR #8200.

The first affected release is RELEASE.2018-08-18T03-49-57Z.

Patches

Fixed in: MinIO AIStor RELEASE.2025-12-20T04-58-37Z

The fix replaces the unbounded bufio.Reader.ReadBytes('\n') call with a byte-at-a-time loop that caps line scanning at 128 KB (csvSplitSize). If no newline is found within this limit, the reader returns an error instead of continuing to buffer.

Binary Downloads

PlatformArchitectureDownload
Linuxamd64minio
Linuxarm64minio
macOSarm64minio
macOSamd64minio
Windowsamd64minio.exe

FIPS Binaries

PlatformArchitectureDownload
Linuxamd64minio.fips
Linuxarm64minio.fips

Package Downloads

Container Images

# Standard
docker pull quay.io/minio/aistor/minio:RELEASE.2025-12-20T04-58-37Z
podman pull quay.io/minio/aistor/minio:RELEASE.2025-12-20T04-58-37Z

# FIPS
docker pull quay.io/minio/aistor/minio:RELEASE.2025-12-20T04-58-37Z.fips
podman pull quay.io/minio/aistor/minio:RELEASE.2025-12-20T04-58-37Z.fips

Homebrew (macOS)

brew install minio/aistor/minio

Workarounds

If upgrading is not immediately possible:

  • Disable S3 Select access via IAM policy. Deny the s3:GetObject action with a condition restricting s3:prefix on sensitive buckets, or more specifically, deny SelectObjectContent requests at a reverse proxy by blocking POST requests with ?select&select-type=2 query parameters.

  • Restrict PutObject permissions. Limit s3:PutObject grants to trusted principals to reduce the attack surface. Note: this reduces risk but does not eliminate the vulnerability since any authorized user can exploit it.

References

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/minio/minio0.0.0-20180815103019-7c14cdb60e53No fix

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/minio/minio. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Remediation status

    No patched version of github.com/minio/minio has shipped for GHSA-h749-fxx7-pwpg yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-h749-fxx7-pwpg is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-h749-fxx7-pwpg. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact _What kind of vulnerability is it? Who is impacted?_ 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:GetObj
O3 Security · Impact-Aware SCA

Is GHSA-h749-fxx7-pwpg in your dependencies?

O3 detects GHSA-h749-fxx7-pwpg across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

GHSA-h749-fxx7-pwpg: minio | O3 Security