CVE-2026-73285 json
RustFS: OPA policy plugin omits ExistingObjectTag conditions, allowing tag-based authorization policies to treat tagged objects as untagged
published 2026-08-12 2 mo ago modified 2026-09-09 1 mo ago also EUVD-2026-57229
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 40%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 2 mo ago
Exploit prediction
0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/rustfs/rustfs/security/advisories/GHSA-5w8r-p896-6vq2 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected products
- rustfs rustfs
Classification
- Weakness
-
- CWE-863 Incorrect Authorization
References
- github.com /rustfs/rustfs/commit/98d3619613722308498494d412797a52ea8ae64d
-
github.com
/rustfs/rustfs/security/advisories/GHSA-5w8r-p896-6vq2
exploit
- github.com /rustfs/rustfs/blob/380ed40b471887014fe21d069b61df9eacca074b/.agents/skills/security-advisory-lessons/referenc
- github.com /rustfs/rustfs/releases/tag/1.0.0-rc.1
Sources
- CVE List CVE-2026-73285
- NVD CVE-2026-73285
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.