CVE-2026-84838 in Rpm
Summary
by MITRE • 09/02/2026
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.
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Analysis
by VulDB Data Team • 09/02/2026
The vulnerability identified in rpmuncompress represents a critical security flaw rooted in improper input validation and command injection weaknesses within the archive processing utility. This specific issue arises when the application processes filenames that contain shell metacharacters without adequate sanitization or escaping prior to their inclusion in system-level command strings. The core technical failure lies in the direct concatenation of user-supplied filename data into a shell invocation context, allowing an attacker to inject arbitrary commands that are executed with the privileges of the invoking process. This type of flaw is classically categorized under CWE-78 Improper Neutralization of Special Elements used in an OS Command and aligns with ATT&CK technique T1059 Command and Scripting Interpreter, where adversaries leverage native system tools to execute malicious payloads.
The operational impact of this vulnerability is significant due to its potential for high-impact exploitation within local environments. Although the attack requires user interaction or integration into automated workflows that invoke rpmuncompress on untrusted files, the consequences of successful execution are severe. An attacker who can trick a user or an automation script into processing a maliciously crafted archive filename gains the ability to execute arbitrary commands with the same permissions as the invoking user. This capability directly compromises the confidentiality, integrity, and availability of data accessible to that user account. For instance, if invoked by a privileged service or administrator, this could lead to full system compromise, allowing for lateral movement, persistence establishment, or complete data exfiltration.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary solution is the deployment of vendor-provided patches that address the input validation logic within rpmuncompress to ensure all special characters are properly escaped before shell execution. In environments where patching may not be immediately feasible, operational mitigations should include restricting file upload capabilities for untrusted users, implementing strict allow-lists for archive filenames in automated workflows, and enforcing principle of least privilege by ensuring that services running rpmuncompress operate with minimal necessary permissions. Additionally, organizations should audit their use of shell-invoking utilities to prevent similar command injection vectors across other system components.