CVE-2025-62506
ADVISORY - githubSummary
Summary
A privilege escalation vulnerability allows service accounts and STS (Security Token Service) accounts with restricted session policies to bypass their inline policy restrictions when performing "own" account operations, specifically when creating new service accounts for the same user.
Details
The vulnerability exists in the IAM policy validation logic in cmd/iam.go. When validating session policies for restricted accounts performing operations on their own account (such as creating service accounts), the code incorrectly relied on the DenyOnly argument.
The DenyOnly flag is used to allow accounts to perform actions related to their own account by only checking if the action is explicitly denied. However, when a session policy (sub-policy) is present, the system should validate that the action is actually allowed by the session policy, not just that it isn't denied.
Attack Scenario
- An administrator creates a service account or STS account with a restricted inline policy (e.g., access only to bucket1 and bucket2)
- The restricted account attempts to create a new service account for itself without specifying any policy restrictions
- Due to the bypass, the new service account is created with full parent privileges instead of being restricted by the inline policy
- The attacker now has escalated privileges beyond the intended restrictions
Impact
Attack Complexity: LOW - Exploitation requires only valid credentials for a restricted service/STS account
Confidentiality: HIGH - Attackers can access buckets and objects beyond their intended restrictions
Integrity: HIGH - Attackers can modify, delete, or create objects outside their authorized scope
Availability: NONE - Does not directly impact service availability
Patches
Fixed in PR https://github.com/minio/minio/pull/21642 Commit: c1a49490c78e9c3ebcad86ba0662319138ace190
Install the release
go install -v github.com/minio/minio@RELEASE.2025-10-15T17-29-55Z
Workarounds
No workarounds available. You can upgrade to the latest version immediately.
Mitigation Steps
- Upgrade MinIO: Update to the latest version containing the fix
- Audit Service Accounts: Review all service accounts created by non-admin accounts
- Revoke Suspicious Accounts: Delete any service accounts that may have been created through exploitation
- Review Access Logs: Check for unauthorized access to sensitive buckets
Resources
- Fix PR: https://github.com/minio/minio/pull/21642
- Affected code: cmd/iam.go (functions: isAllowedBySessionPolicyForServiceAccount, isAllowedBySessionPolicy)
Common Weakness Enumeration (CWE)
Incorrect Authorization
Incorrect Authorization
Bitnami
BIT-minio-2025-62506
2.8
CVSS SCORE
8.1high| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| minio | bitnami | - | - | <2025.10.15 | 2025.10.15 |
CVSS:3 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 attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a 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 user.
An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any or all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
There is no impact to availability within the impacted component.
NIST
2.8
CVSS SCORE
8.1highGitHub
2.8
CVSS SCORE
8.1highAlpine
-
Chainguard
CGA-vcgp-ggph-vrjr
-
minimos
MINI-r348-f45c-c4fx
-