Critical severity · published Jan 8, 2026
CVE-2026-22043
RustFS has IAM deny_only Short-Circuit that Allows Privilege Escalation via Service Account Minting
9.8
CVSS
0.4%
EPSS
No
On KEV
Description
RustFS is a distributed object storage system built in Rust. In versions 1.0.0-alpha.13 through 1.0.0-alpha.78, a flawed `deny_only` short-circuit in RustFS IAM allows a restricted service account or STS credential to self-issue an unrestricted service account, inheriting the parent’s full privileges. This enables privilege escalation and bypass of session/inline policy restrictions. Version 1.0.0-alpha.79 fixes the issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% 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.13, < 1.0.0-alpha.79 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-22043
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-22043
Exploit
https://github.com/rustfs/rustfs/security/advisories/GHSA-xgr5-qc6w-vcg9
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