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NVD / CVE Program· CNA GitHub_M

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

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.46% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: rustfs rustfs 1.0.0-rc.1.

Low priority for now. Upgrade to rustfs rustfs 1.0.0-rc.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Aug 12, 2026
Updated
Sep 9, 2026
EPSS
0.4% · 40th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • rustfs rustfs

    • >= 1.0.0-alpha.64, < 1.0.0-rc.1affected

Same product

rustfs: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-68926RustFS has a gRPC Hardcoded Token Authentication Bypass
    49Plan
  • CVE-2026-45039RustFS: Internode RPC HMAC secret falls back to public default credential, enabling peer impersonation
    39Monitor
  • CVE-2026-45043RustFS: ImportIam Allows Creation of Backdoor Service Accounts Under Any Parent Including Root
    37Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-73265Aug 12, 2026 · RustFS: Version-specific object reads authorize the non-version action
    26Monitor
  • ← EarlierCVE-2026-73284Aug 12, 2026 · RustFS: AddServiceAccount Handler Allows Creation of Root-Parent Service Accounts
    35Monitor
  • Later →CVE-2026-73286Aug 12, 2026 · RustF: Request headers can populate server-derived IAM condition keys, letting a caller satisfy identity-based policy conditions
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
rustfs rustfs1.0.0-rc.1 · descriptionVendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-732860 days apartRustF: Request headers can populate server-derived IAM condition keys, letting a caller satisfy identity-based policy conditions
    32Monitor
  • CVE-2026-732890 days apartRustFS: ForAllValues/ForAnyValue negated string conditions are transposed, inverting IAM and bucket-policy decisions
    32Monitor
  • CVE-2026-4504276 days apartRustFS: UploadPartCopy Does Not Enforce Destination Bucket Policy on Copy Source
    28Monitor
  • CVE-2026-732900 days apartRustFS: Anonymous ListObjectVersions bypasses RestrictPublicBuckets through the ListBucket fallback
    21Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records