Threats / MinIO / CVE-2023-28434
CVE-2023-28434
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
MinIO vulnerability
MinIO security feature bypass allows authenticated attackers with broad S3 permissions to bypass bucket name validation and write objects to arbitrary buckets via crafted PostPolicyBucket requests, enabling privilege escalation.
Verdict
Today item — known-exploited.
An authenticated attacker with wildcard S3 permissions and Console API access can craft requests to bypass metadata bucket name checks, write objects to unauthorized buckets, and escalate privileges within the MinIO deployment.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-09-19).
Probability (EPSS)
EPSS 0.06736 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: MinIO, MinIO. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-269 Improper Privilege Management — weakness family: Authorization / access control.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I obtain or compromise credentials with arn:aws:s3:::* permission scope and Console API access to the MinIO instance.
Business
An insider or external threat actor gains initial authenticated access with overly permissive IAM policies.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I craft a malicious PostPolicyBucket request that bypasses the metadata bucket name validation check.
Business
The security control designed to restrict bucket access is circumvented through request manipulation.
3
Lateral reach — past segmentation narrative 3
Attacker
I use the crafted request to write objects into buckets I should not have access to, including sensitive or restricted buckets.
Business
Confidential data buckets are compromised; unauthorized modifications to critical data occur.
4
Data at risk — exfiltration narrative 4
Attacker
I escalate my privileges by placing objects that modify bucket policies, access controls, or administrative configurations.
Business
The attacker gains administrative control over the MinIO deployment and can access or exfiltrate all stored data.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05