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CVE-2026-27607

RustFS's Missing Post Policy Validation leads to Arbitrary Object Write

Published: Feb 25, 2026Updated: Feb 25, 2026 Sources: CVE List NVD GHSA BDUCWE-20
NVD MITRE
8.1CVSSHIGH
EPSS Score
0.3%
Top 82.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

RustFS is a distributed object storage system built in Rust. In versions 1.0.0-alpha.56 through 1.0.0-alpha.82, RustFS does not validate policy conditions in presigned POST uploads (PostObject), allowing attackers to bypass content-length-range, starts-with, and Content-Type constraints. This enables unauthorized file uploads exceeding size limits, uploads to arbitrary object keys, and content-type spoofing, potentially leading to storage exhaustion, unauthorized data access, and security bypasses. Version 1.0.0-alpha.83 fixes the issue.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:NI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-20CWE-863

Affected Products

rustfsrustfs
Library
OSS Libraries / generic-library
rustfscrates.ioOSS Libraries
RustFSСообщество свободного программного обеспечения
On-prem
Operating Systems / linux-distro
rustfsoss-projectOSS Librariesaka rustfs
crates.iopackage-ecosystemOSS Libraries
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Initial Access
View detailed technique mapping

References

https://github.com/rustfs/rustfs/security/advisories/GHSA-w5fh-f8xh-5x3p
github.com
https://nvd.nist.gov/vuln/detail/CVE-2026-27607
nvd.nist.gov
https://github.com/rustfs/rustfs
github.com
and 4 more references View all →

Timeline

Published
Feb 25, 2026
Last Updated
Feb 25, 2026

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