CVE-2026-34204
ADVISORY - githubSummary
Impact
What kind of vulnerability is it? Who is impacted?
A flaw in extractMetadataFromMime() allows any authenticated user with s3:PutObject permission to inject internal server-side encryption metadata into objects by sending crafted X-Minio-Replication-* headers on a normal PutObject request. The server unconditionally maps these headers to X-Minio-Internal-* encryption metadata without verifying that the request is a legitimate replication request. Objects written this way carry bogus encryption keys and become permanently unreadable through the S3 API.
Any authenticated user or service with s3:PutObject permission on any bucket can make objects permanently unreadable by injecting fake SSE encryption metadata. The attacker sends a standard PutObject request with X-Minio-Replication-Server-Side-Encryption-* headers but without the X-Minio-Source-Replication-Request header that marks legitimate replication traffic. The server maps these headers to internal encryption metadata (X-Minio-Internal-Server-Side-Encryption-Sealed-Key, etc.), causing all subsequent GetObject and HeadObject calls to treat the object as encrypted with keys that do not exist.
This is a targeted denial-of-service vulnerability. An attacker can selectively corrupt individual objects or entire buckets. The ReplicateObjectAction IAM permission is never checked because the request is a normal PutObject, not a replication request.
Affected component: cmd/handler-utils.go, function extractMetadataFromMime().
Affected Versions
All MinIO releases through the final release of the minio/minio open-source project.
The vulnerability was introduced in commit 468a9fae83e965ecefa1c1fdc2fc57b84ece95b0 ("Enable replication of SSE-C objects", PR #19107, 2024-03-28). The first affected release is RELEASE.2024-03-30T09-41-56Z.
Patches
Fixed in: MinIO AIStor RELEASE.2026-03-26T21-24-40Z
Binary Downloads
| Platform | Architecture | Download |
|---|---|---|
| Linux | amd64 | minio |
| Linux | arm64 | minio |
| macOS | arm64 | minio |
| macOS | amd64 | minio |
| Windows | amd64 | minio.exe |
FIPS Binaries
| Platform | Architecture | Download |
|---|---|---|
| Linux | amd64 | minio.fips |
| Linux | arm64 | minio.fips |
Package Downloads
| Format | Architecture | Download |
|---|---|---|
| DEB | amd64 | minio_20260326212440.0.0_amd64.deb |
| DEB | arm64 | minio_20260326212440.0.0_arm64.deb |
| RPM | amd64 | minio-20260326212440.0.0-1.x86_64.rpm |
| RPM | arm64 | minio-20260326212440.0.0-1.aarch64.rpm |
Container Images
# Standard
docker pull quay.io/minio/aistor/minio:RELEASE.2026-03-26T21-24-40Z
podman pull quay.io/minio/aistor/minio:RELEASE.2026-03-26T21-24-40Z
# FIPS
docker pull quay.io/minio/aistor/minio:RELEASE.2026-03-26T21-24-40Z.fips
podman pull quay.io/minio/aistor/minio:RELEASE.2026-03-26T21-24-40Z.fips
Homebrew (macOS)
brew install minio/aistor/minio
Workarounds
If upgrading is not immediately possible:
Restrict replication headers at a reverse proxy / load balancer. Drop or reject any request containing
X-Minio-Replication-Server-Side-Encryption-*headers that does not also carryX-Minio-Source-Replication-Request. This blocks the injection path without modifying the server.Audit IAM policies. Limit
s3:PutObjectgrants to trusted principals. While this reduces the attack surface, it does not eliminate the vulnerability since any authorized user can exploit it.
References
- Introducing commit:
468a9fae8(PR #19107) - MinIO AIStor
Common Weakness Enumeration (CWE)
Improper Authentication
Improper Authentication
GitHub
2.8
CVSS SCORE
7.1high| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| github.com/minio/minio | golang | - | - | >=0.0.0-20240328174456-468a9fae83e9,<=0.0.0-20260212201848-7aac2a2c5b7c | Not yet available |
CVSS:4 Severity and metrics
The CVSS metrics represent different qualitative aspects of a vulnerability that impact the overall score, as defined by the CVSS Specification.
The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone). One example of an Adjacent attack would be an ARP (IPv4) or neighbor discovery (IPv6) flood leading to a denial of service on the local LAN segment (e.g., CVE-2013-6014).
Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.
The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges.
There is no loss of confidentiality within the Vulnerable System.
There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Vulnerable System; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the Vulnerable System (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).
There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
NIST
2.8
CVSS SCORE
7.1highAlpine
-
GoLang
-
Bitnami
BIT-minio-2026-34204
-
CVSS SCORE
7.1highChainguard
CGA-wgj6-g5p5-m9rw
-
minimos
MINI-8666-286m-47gj
-
minimos
MINI-c6p4-3gv7-fg4h
-