Vulnerability · Published Oct 16, 2025 · Assigned by GitHub_M
CVE-2025-62506MinIO vulnerable to privilege escalation via session policy bypass in service accounts and STS
High 8.1
In plain English
A high-severity incorrect authorization in minio from minio. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official description
MinIO is a high-performance object storage system. In all versions prior to RELEASE.2025-10-15T17-29-55Z, 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 operations on their own account, specifically when creating new service accounts for the same user. The vulnerability exists in the IAM policy validation logic where the code incorrectly relied on the DenyOnly argument when validating session policies for restricted accounts. When a session policy is present, the system should validate that the action is allowed by the session policy, not just that it is not denied. An attacker with valid credentials for a restricted service or STS account can create a new service account for itself without policy restrictions, resulting in a new service account with full parent privileges instead of being restricted by the inline policy. This allows the attacker to access buckets and objects beyond their intended restrictions and modify, delete, or create objects outside their authorized scope. The vulnerability is fixed in version RELEASE.2025-10-15T17-29-55Z.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/minio/minio | 0.0.0-20251015170045-c1a49490c78e | GHSA-jjjj-jwhf-8rgr |
| Go | github.com/minio/minio | 0.0.0-20251015170045-c1a49490c78e | GO-2025-4034 |
Affected products (as reported)
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
References
- https://github.com/minio/minio/security/advisories/GHSA-jjjj-jwhf-8rgr x_refsource_CONFIRM
- https://github.com/minio/minio/pull/21642 x_refsource_MISC
- https://github.com/minio/minio/commit/c1a49490c78e9c3ebcad86ba0662319138ace190 x_refsource_MISC
- https://github.com/minio/minio/issues/21647
- https://news.ycombinator.com/item?id=45684035
- https://github.com/minio/minio/discussions/21655