High severity · published Aug 12, 2026
CVE-2026-73285
RustFS: OPA policy plugin omits ExistingObjectTag conditions, allowing tag-based authorization policies to treat tagged objects as untagged
7.5
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 40% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RU
rustfs · rustfs
>= 1.0.0-alpha.64, < 1.0.0-rc.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-73285
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-73285
github.com
https://github.com/rustfs/rustfs/blob/380ed40b471887014fe21d069b61df9eacca074b/.agents/skills/security-advisory-lessons/references/advisory-patterns.md?plain=1#L47
github.com
https://github.com/rustfs/rustfs/commit/98d3619613722308498494d412797a52ea8ae64d
github.com
https://github.com/rustfs/rustfs/releases/tag/1.0.0-rc.1
github.com
https://github.com/rustfs/rustfs/security/advisories/GHSA-5w8r-p896-6vq2
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