EUVD-2026-19867
GHSA-mx42-j6wv-px98
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from Vendor (github) · only source for this CVE.
CVSS VectorVendor: github
Lifecycle Timeline
3DescriptionCVE.org
RustFS is a distributed object storage system built in Rust. Prior to alpha.90, RustFS contains a missing authorization check in the multipart copy path (UploadPartCopy). A low-privileged user who cannot read objects from a victim bucket can still exfiltrate victim objects by copying them into an attacker-controlled multipart upload and completing the upload. This breaks tenant isolation in multi-user / multi-tenant deployments. This vulnerability is fixed in alpha.90.
AnalysisAI
RustFS alpha versions prior to alpha.90 allow authenticated users with limited permissions to bypass authorization checks in the multipart copy operation (UploadPartCopy), enabling exfiltration of objects from buckets they cannot directly read. This breaks tenant isolation in multi-tenant deployments by allowing a low-privileged user to copy victim objects into their own multipart upload and complete the transfer without proper authorization validation.
Technical ContextAI
RustFS is a distributed object storage system written in Rust. The vulnerability exists in the UploadPartCopy code path, which handles copying object parts during multipart upload operations. The root cause is a missing authorization check (CWE-862: Missing Authorization) that fails to validate whether the authenticated user has read access to the source object before permitting the copy operation. In multi-tenant environments, this allows a user authenticated to one tenant or bucket context to access objects from other tenants by leveraging the multipart upload mechanism, which apparently has weaker or missing permission validation compared to standard read operations.
RemediationAI
Upgrade to RustFS alpha.90 or later, which includes the fix for the missing authorization check in the UploadPartCopy operation. No workarounds are available; patching is the only remediation. Organizations should prioritize this upgrade if RustFS is deployed in multi-tenant environments. Refer to the GitHub security advisory at https://github.com/rustfs/rustfs/security/advisories/GHSA-mx42-j6wv-px98 for detailed patch information and deployment guidance.
RustFS (alpha.13 to alpha.78) has a path traversal in /rustfs/rpc/read_file_stream that allows reading arbitrary files o
RustFS (alpha.13 to alpha.78) has a privilege escalation where restricted service accounts can self-issue unrestricted c
Stored XSS in RustFS distributed object storage system before 1.0.0-alpha.83. Malicious JavaScript persists in stored ob
Incorrect IAM permission validation in RustFS prior to version 1.0.0-alpha.79 permits principals with export-only permis
RustFS versions 1.0.0-alpha.1 through 1.0.0-alpha.79 expose the shared HMAC secret in server logs when processing invali
Authentication bypass in RustFS distributed object storage (versions prior to 1.0.0-beta.2) allows unauthenticated remot
Privilege escalation in RustFS distributed object storage before 1.0.0-beta.2 lets a low-privileged user holding ImportI
Stored cross-site scripting in RustFS Console (0.1.7 through 0.1.9) lets an attacker upload an HTML payload disguised as
Privilege escalation in RustFS prior to version 1.0.0-beta.11 allows any authenticated user holding CreateServiceAccount
Unauthenticated denial of service and information disclosure in RustFS distributed object storage prior to version 1.0.0
License-enforcement bypass in RustFS distributed object storage (versions prior to 1.0.0-beta.2) stems from a hardcoded
Cross-tenant object injection in RustFS 1.0.0-beta.4 lets a tenant holding only PutObject rights on their own bucket wri
Same weakness CWE-862 – Missing Authorization
View allSame technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today