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

Status: published. Published: 2026-09-01. Updated: 2026-11-03.

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.

## Remediation

- workaround: To mitigate this vulnerability, avoid using `rpmuncompress -x` (or a build workflow that invokes it via %{__rpmuncompress}) on `.gem` files from untrusted sources. Before extraction, rename `.gem` files to remove any RPM macro syntax (e.g., `%(...)`) or utilize an alternative extraction tool that does not expand RPM macros in filenames. In automated environments, implement validation to reject or sanitize untrusted archive names prior to processing (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Hardened Images (rpm-main): ≥ 6.1.0-1.hum1; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (rpm): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (rpm): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (rpm): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (rpm): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (rpm): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 7 (high); CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.19% as of 2026-11-02; percentile 9.12%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-78

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2026:66637 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-84233 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2478409 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-84233; retrieved 2026-11-03; source updated 2026-11-03

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-84233; retrieved 2026-11-03; source updated Not reported

Revision: 0ac72f7803d70f13c07d8205aa824a732cff29124b41be8bf366e688f9e0b63d

Canonical: https://y2.dev/cve/CVE-2026-84233

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