What is the CVSS score of CVE-2021-21390?

CVE-2021-21390 has a CVSS 3.1 base score of 5.9 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N. EPSS exploitation probability: 0.9%.

Is there a public PoC exploit available for CVE-2021-21390?

Yes, a public proof-of-concept exploit is available for CVE-2021-21390. Prioritise patching immediately. EPSS: 0.9%.

Is there a patch available for CVE-2021-21390?

Yes, a patch is available for CVE-2021-21390. Update the affected software to the latest version immediately.

Minio CVE-2021-21390

MEDIUM

Improper Enforcement of Message Integrity During Transmission (CWE-924)

2021-03-19 security-advisories@github.com

Information Disclosure Minio

5.9

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.9 MEDIUM

AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Lifecycle Timeline

CVE Published

Mar 19, 2021 - 16:15 nvd

MEDIUM 5.9

DescriptionNVD

MinIO is an open-source high performance object storage service and it is API compatible with Amazon S3 cloud storage service. In MinIO before version RELEASE.2021-03-17T02-33-02Z, there is a vulnerability which enables MITM modification of request bodies that are meant to have integrity guaranteed by chunk signatures. In a PUT request using aws-chunked encoding, MinIO ordinarily verifies signatures at the end of a chunk. This check can be skipped if the client sends a false chunk size that is much greater than the actual data sent: the server accepts and completes the request without ever reaching the end of the chunk + thereby without ever checking the chunk signature. This is fixed in version RELEASE.2021-03-17T02-33-02Z. As a workaround one can avoid using "aws-chunked" encoding-based chunk signature upload requests instead use TLS. MinIO SDKs automatically disable chunked encoding signature when the server endpoint is configured with TLS.

AnalysisAI

MinIO is an open-source high performance object storage service and it is API compatible with Amazon S3 cloud storage service. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified under CWE-924. MinIO is an open-source high performance object storage service and it is API compatible with Amazon S3 cloud storage service. In MinIO before version RELEASE.2021-03-17T02-33-02Z, there is a vulnerability which enables MITM modification of request bodies that are meant to have integrity guaranteed by chunk signatures. In a PUT request using aws-chunked encoding, MinIO ordinarily verifies signatures at the end of a chunk. This check can be skipped if the client sends a false chunk size that is much greater than the actual data sent: the server accepts and completes the request without ever reaching the end of the chunk + thereby without ever checking the chunk signature. This is fixed in version RELEASE.2021-03-17T02-33-02Z. As a workaround one can avoid using "aws-chunked" encoding-based chunk signature upload requests instead use TLS. MinIO SDKs automatically disable chunked encoding signature when the server endpoint is configured with TLS. Affected products include: Minio.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.