RustFS has IAM Incorrect Authorization in ImportIam that Allows Privilege Escalation

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 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 · score source

EPSS

• CVE-2026-22042: 0.43% estimated exploitation activity in the next 30 days; percentile 37.79 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The 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. --- Details In ImportIam, the authorization check is implemented as follows: However, this code resides in the Import IAM operation (struct ImportIam {}), which performs state-changing IAM writes. The expected behavior is to validate against AdminAction::ImportIAMAction (or an equivalent import-specific admin action), not ExportIAMAction. --- PoC Prerequisites 1. A RustFS deployment with IAM enabled. 2. An IAM user or role that has Export IAM permission but does not have Import IAM or full admin permissions. 3. Access credentials for that user. Steps 1. Create or obtain an IAM principal with permission…

Published by the source

8 Jan 2026, 20:36 UTC

Last modified by the source

8 Jan 2026, 20:36 UTC

Source last checked

26 Oct 2026, 15:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-vcwh-pff9-64cc

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# Patch Next advisory brief: CVE-2026-22042

Advisory: RustFS has IAM Incorrect Authorization in ImportIam that Allows Privilege Escalation
IDs: CVE-2026-22042, GHSA-vcwh-pff9-64cc
Record: https://patchnext.com/advisories/cve-2026-22042 (revision 1, source checked 26 Oct 2026, 15:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: rustfs 1.0.0-alpha.79. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io rustfs: affected < 1.0.0-alpha.79; fixed in 1.0.0-alpha.79

## Suggested inspection (read-only)
- crates.io rustfs: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on rustfs.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-vcwh-pff9-64cc (GitHub-reviewed advisory GHSA-vcwh-pff9-64cc lists affected ranges: crates.io rustfs >=0 <1.0.0-alpha.79)

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