CVE-2026-34041
Description
A flaw was found in act, a project that allows local execution of GitHub Actions. This vulnerability arises from the unconditional processing of deprecated workflow commands, specifically ::set-env:: and ::add-path::, which were previously disabled due to environment injection risks. A remote attacker can exploit this by injecting these commands when a workflow step echoes untrusted data to standard output. This allows the attacker to set arbitrary environment variables or modify the system's execution path for all subsequent steps within the job, potentially leading to privilege escalation or arbitrary code execution.
Statement
Red Hat Product Security has determined that this vulnerability does not affect any currently supported Red Hat product. This assessment may evolve based on further analysis and discovery. For more information about this vulnerability and the products it affects, please see the linked references.
Mitigation
To mitigate this issue, ensure that `act` is only used with trusted GitHub Actions workflows. Review all workflow steps to prevent the echoing of untrusted data to standard output, which could allow for the injection of deprecated workflow commands (`::set-env::` and `::add-path::`) and subsequent privilege escalation or arbitrary code execution.
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability,Non-Repudiation
Technical Impact: Execute Unauthorized Code or Commands; DoS: Crash, Exit, or Restart; Read Files or Directories; Modify Files or Directories; Read Application Data; Modify Application Data; Hide Activities
Attackers could execute unauthorized operating system commands, which could then be used to disable the product, or read and modify data for which the attacker does not have permissions to access directly. Since the targeted application is directly executing the commands instead of the attacker, any malicious activities may appear to come from the application or the application's owner.
Frequently Asked Questions
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