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

> A flawed IAM short-circuit in RustFS allows restricted service accounts to self-issue unrestricted credentials, enabling privilege escalation and policy bypass.

- **Severity:** Medium 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Jan 2026
- **Updated:** 8 Jan 2026
- **Also known as:** GHSA-xgr5-qc6w-vcg9

## What is CVE-2026-22043?

CVE-2026-22043 is a medium-severity vulnerability in rustfs, published on 8 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-522 (Insufficiently Protected Credentials), CWE-284 (Improper Access Control), CWE-269 (Improper Privilege Management)

## Which versions are affected by CVE-2026-22043?

2 open source packages ship an affected version, including rustfs. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `rustfs` | crates.io | From 1.0.0-alpha.13 | 1.0.0-alpha.79 |
| `rustfs` | crates.io | From 1.0.0-alpha.13 | 1.0.0-alpha.79 |

Products: Rustfs Rustfs.

## How do I fix CVE-2026-22043?

Upgrade rustfs to 1.0.0-alpha.79 or later.

## Is CVE-2026-22043 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-22043 exists.

## Other vulnerabilities in rustfs

- [CVE-2025-68926](https://insights.sbomify.com/CVE-2025-68926/): RustFS has a gRPC Hardcoded Token Authentication Bypass (critical 9.8)
- [CVE-2026-27822](https://insights.sbomify.com/CVE-2026-27822/): Rust has Critical Stored XSS in Preview Modal, leading to Administrative Account Takeover (critical 9.1)
- [CVE-2025-68705](https://insights.sbomify.com/CVE-2025-68705/): RustFS Path Traversal Vulnerability (high 8.8)
- [CVE-2026-40937](https://insights.sbomify.com/CVE-2026-40937/): RustFS: Missing admin authorization on notification target endpoints allows unauthenticated configuration of event webhooks (high 8.3)
- [CVE-2026-27607](https://insights.sbomify.com/CVE-2026-27607/): RustFS's Missing Post Policy Validation leads to Arbitrary Object Write (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22043 and fix it if it is affected.

What it is: CVE-2026-22043 is a medium-severity vulnerability in rustfs, published on 8 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-22043 exists.

Affected packages and fixed versions:
- rustfs (crates.io): affected from 1.0.0-alpha.13; fixed in 1.0.0-alpha.79
- rustfs (crates.io): affected from 1.0.0-alpha.13; fixed in 1.0.0-alpha.79

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-22043/ (Markdown: https://insights.sbomify.com/CVE-2026-22043/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22043
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22043
- OSV: https://osv.dev/vulnerability/CVE-2026-22043

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22043/
Summaries are generated and may contain mistakes; the official description above is the record.