Is there a public exploit for CVE-2023-28434?

Yes. CVE-2023-28434 is listed in the CISA Known Exploited Vulnerabilities catalog, meaning exploitation has been observed in the wild.

Is there a proof of concept for CVE-2023-28434?

Yes — 1 proof-of-concept entry is linked on this page, from public repositories and community submissions. They are listed for authorised testing only.

How severe is CVE-2023-28434?

CVE-2023-28434 scores CVSS 8.8 (v3.1), rated high. EPSS puts the chance of exploitation in the next 30 days at 7.92%.

What does CVE-2023-28434 affect?

CVE-2023-28434 affects MinIO MinIO.

8.8 High

Minio is a Multi-Cloud Object Storage framework.

CVE-2023-28434 Exploited

Impact An attacker can use crafted requests to bypass metadata bucket name checking and put an object into any bucket while processing PostPolicyBucket. To carry out this attack, the attacker requires credentials with arn:aws:s3::: permission, as well as enabled Console API access. Patches commit 67f4ba154a27a1b06e48bfabda38355a010dfca5 Author: Aditya Manthramurthy Date: Sun Mar 19 21:15:20 2023 -0700 fix: post policy request security bypass (#16849) Workarounds Browser API access must be enabled turning off MINIOBROWSER=off allows for this workaround. References The vulnerable code: go // minio/cmd/generic-handlers.go func setRequestValidityHandler(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r http.Request) { // ... // For all other requests reject access to reserved buckets bucketName, := request2BucketObjectName(r) if isMinioReservedBucket(bucketName) || isMinioMetaBucket(bucketName) { if !guessIsRPCReq(r) && !guessIsBrowserReq(r) && !guessIsHealthCheckReq(r) && !guessIsMetricsReq(r) && !isAdminReq(r) && !isKMSReq(r) { if ok { tc.FuncName = "handler.ValidRequest" tc.ResponseRecorder.LogErrBody = true } writeErrorResponse(r.Context(), w,…

Being exploited in the wild

Catalogued 19 September 2023 · US federal remediation deadline 10 October 2023

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Exploit code is also public: Public PoC

Public PoCAbelChe/evil_minio318 stars

Assessment

CVSS: 8.8 (v3.1)
Severity: High
EPSS: 7.92% chance of exploitation in the next 30 days
Known exploited: Yes — listed in the CISA KEV catalog
Exploit availability: CISA KEV, Public PoC
Published: 22 March 2023
Last updated: 17 June 2026
Affected: MinIO · minio · MinIO · minio · github.com/minio/minio
Weakness: CWE-269
Assigner: security-advisories@github.com

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

At the source

References

Community proofs of concept

No community proof of concept yet. If you have one for a published vulnerability and the right to share it, add it below — it will appear here once reviewed.

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