# CVE-2026-84838: Rpm: command injection in rpmuncompress via unescaped filenames passed to popen()

Status: published. Published: 2026-09-02. Updated: 2026-11-03.

A flaw was found in rpmuncompress. This command injection vulnerability allows a local attacker to execute arbitrary commands. This occurs when rpmuncompress processes a specially crafted archive filename containing shell metacharacters, which are not properly escaped before being passed to shell command strings. Successful exploitation requires user interaction, where a user or automated workflow invokes rpmuncompress on the malicious file, leading to high impact on the confidentiality, integrity, and availability of data accessible to the invoking user.

## Remediation

- workaround: To mitigate this issue, avoid processing untrusted archive filenames with `rpmuncompress` or any workflows that invoke `%{__rpmuncompress}`. Before any build or extraction steps, rename source and patch archives to remove any shell metacharacters from their filenames. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Hardened Images (rpm-main): ≥ 6.1.0-1.3.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: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 1.10% as of 2026-11-02; percentile 65.81%

- 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-2026:82378 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-84838 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2462222 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-84838; retrieved 2026-11-03; source updated 2026-11-03

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-84838; retrieved 2026-11-03; source updated Not reported

Revision: fecedc2548579361659f614c46fe6864b456bfc39e8bfe6133cf19bf29e0efac

Canonical: https://y2.dev/cve/CVE-2026-84838

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