What’s Vulnerable › Vulnerabilities

CVE-2026-73285: RustFS: OPA policy plugin omits ExistingObjectTag conditions, allowing tag-based authorization policies to treat tagged objects as untagged

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-12 · updated 2026-09-09
• Weakness: CWE-863

Description

RustFS is a distributed object storage system built in Rust. From 1.0.0-alpha.64 until 1.0.0-rc.1, RustFS external OPA authorization enabled by RUSTFS_POLICY_PLUGIN_URL in crates/iam/src/sys.rs sets PreparedIamAuth.needs_existing_object_tag incorrectly for PreparedIamMode::Opa, causing maybe_merge_object_tag_conditions to omit s3:ExistingObjectTag/* values and allowing authenticated users to bypass tag-based policy restrictions. This issue is fixed in version 1.0.0-rc.1.

Affected products

• rustfs: from 1.0.0-alpha.64, < 1.0.0-rc.1

References

• https://github.com/rustfs/rustfs/blob/380ed40b471887014fe21d069b61df9eacca074b/.agents/skills/security-advisory-lessons/references/advisory-patterns.md?plain=1#L47
• https://github.com/rustfs/rustfs/commit/98d3619613722308498494d412797a52ea8ae64d
• https://github.com/rustfs/rustfs/releases/tag/1.0.0-rc.1
• https://github.com/rustfs/rustfs/security/advisories/GHSA-5w8r-p896-6vq2
• https://github.com/rustfs/rustfs/security/advisories/GHSA-5w8r-p896-6vq2

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