Missing Authentication for Critical Function Affecting github.com/minio/minio/cmd package, versions >=0.0.0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-GOLANG-GITHUBCOMMINIOMINIOCMD-16068910
- published15 Apr 2026
- disclosed14 Apr 2026
- creditArvin Shivram
Introduced: 14 Apr 2026
CVE-2026-40344 (opens in a new tab)How to fix?
There is no fixed version for github.com/minio/minio/cmd.
Overview
github.com/minio/minio/cmd is an open source object storage server compatible with Amazon S3 APIs.
Affected versions of this package are vulnerable to Missing Authentication for Critical Function via the PutObjectExtractHandler, PutObjectHandler, and PutObjectPartHandler function. An attacker can gain unauthorized write access to arbitrary buckets by sending specially crafted requests with a valid access key but without a valid cryptographic signature, exploiting missing or bypassed signature verification in certain authentication flows.
Note: This is only exploitable if the attacker possesses a valid access key with WRITE permissions and targets a bucket name.
Workaround
This vulnerability can be mitigated by blocking requests containing the header X-Amz-Content-Sha256: STREAMING-UNSIGNED-PAYLOAD-TRAILER at the load balancer, reverse proxy, or WAF layer, and by restricting WRITE permissions to trusted principals.