RustFS has IAM Incorrect Authorization in ImportIam that Allows Privilege Escalation

published 2026-01-08 10 mo ago modified 2026-06-17 4 mo ago also GHSA-vcwh-pff9-64cc , EUVD-2026-1472

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits: 0; none known

RustFS is a distributed object storage system built in Rust. Prior to version 1.0.0-alpha.79, he `ImportIam` admin API validates permissions using `ExportIAMAction` instead of `ImportIAMAction`, allowing a principal with export-only IAM permissions to perform import operations. Since importing IAM data performs privileged write actions (creating/updating users, groups, policies, and service accounts), this can lead to unauthorized IAM modification and privilege escalation. Version 1.0.0-alpha.79 fixes the issue.

Patch / fix

fixed in 1

crates.io rustfs 1.0.0-alpha.79

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 10 mo ago (2026-01-08)

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/rustfs/rustfs/security/advisories/GHSA-vcwh-pff9-64cc referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
CNA	4.0	5.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/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
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
crates.io	rustfs	<1.0.0-alpha.79	1.0.0-alpha.79

Affected products

rustfs rustfs

Classification

Weakness

CWE-285 Improper Authorization
CWE-863 Incorrect Authorization

References

github.com /rustfs/rustfs/security/advisories/GHSA-vcwh-pff9-64cc
exploit, web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-22042
advisory
github.com /rustfs/rustfs
package

Sources

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.

Summary