# CVE-2026-84233: Rpm: command execution via macro expansion in `rpmuncompress -x` for crafted `.gem` filenames

> A local attacker can execute arbitrary commands via crafted .gem filenames processed by rpmuncompress, compromising the invoking account.

- **Severity:** High 7.0 (`CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 1 Sep 2026
- **Updated:** 2 Oct 2026
- **Also known as:** AZL-99369, BELL-CVE-2026-84233, DEBIAN-CVE-2026-84233, ECHO-c875-8817-b874, GHSA-j9c4-6ppm-mvh4, RHSA-2026:66637, UBUNTU-CVE-2026-84233

## What is CVE-2026-84233?

CVE-2026-84233 is a high-severity command injection vulnerability in Red Hat Enterprise Linux 10, published on 1 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A flaw was found in rpm. A local attacker could supply a specially crafted `.gem` filename containing RPM macro syntax. When a user or automated workflow invokes `rpmuncompress -x` on this file, the macro expansion occurs during command construction. This allows the attacker to execute arbitrary commands with the privileges of the invoking account, leading to a compromise of confidentiality, integrity, and availability.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-84233?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `python3-rpm` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-apidocs` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-build` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-build-libs` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-cron` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-devel` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-libs` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-audit` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-dbus-announce` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-fapolicyd` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-fsverity` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-ima` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-prioreset` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-selinux` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-syslog` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-systemd-inhibit` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-plugin-unshare` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-sign` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |
| `rpm-sign-libs` | Red Hat:hummingbird:1 | All versions | 0:6.1.0-1.hum1 |

## How do I fix CVE-2026-84233?

Apply the vendor's patch.

## Is CVE-2026-84233 being exploited?

There is no known exploitation of CVE-2026-84233 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-84233 and fix it if it is affected.

What it is: CVE-2026-84233 is a high-severity command injection vulnerability in Red Hat Enterprise Linux 10, published on 1 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-84233 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-84233/ (Markdown: https://insights.sbomify.com/CVE-2026-84233/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-84233
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-84233
- OSV: https://osv.dev/vulnerability/CVE-2026-84233

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-84233/
Summaries are generated and may contain mistakes; the official description above is the record.