Improper Verification of Cryptographic Signature Affecting github.com/chainguard-forks/minio/cmd package, versions <RELEASE.2026-09-22T19-25-18Z
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.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMCHAINGUARDFORKSMINIOCMD-22398876
- published10 Nov 2026
- disclosed5 Nov 2026
- creditorenyomtov
Introduced: 5 Nov 2026
NewCVE-2026-122267 Â (opens in a new tab)How to fix?
Upgrade github.com/chainguard-forks/minio/cmd to version RELEASE.2026-09-22T19-25-18Z or higher.
Overview
Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature via the extractSignedHeaders function in Signature V4 verification. An attacker holding a presigned PUT URL can replay it with an unsigned x-amz-copy-source header, causing MinIO to copy an object the signing key can read from another bucket into the URL’s destination; the attacker can then read the copied object from that destination, turning a write-only upload grant into access to data readable by the signing key. The same unsigned-header gap affects requests authenticated with an Authorization header.
Workarounds
- Do not issue presigned URLs to untrusted parties; this reduces exposure to the presigned-URL attack path, but does not mitigate the affected Authorization-header path.