CVE-2026-119704 in Bastille
Summary
by MITRE • 10/30/2026
Bastille through 1.4.4 contains a symlink following vulnerability in the cp.sh, rcp.sh and jcp.sh subcommands that allows jailed users to escape jail isolation. Attackers inside a jail can plant symlinks pointing to host paths or other jail roots, so administrator-run copies overwrite or read host files with root privileges.
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Analysis
by VulDB Data Team • 10/30/2026
The vulnerability identified in Bastille versions through 1.4.4 represents a critical failure in the implementation of file system isolation within containerized environments, specifically affecting the cp.sh, rcp.sh, and jcp.sh subcommands. This flaw is classified as a symlink following vulnerability, which falls under the broader category of CWE-59: Improper Link Resolution Before File Access. In secure systems designed to enforce strict boundaries between isolated execution environments, such as jails or containers, it is imperative that all file operations respect these boundaries and do not traverse symbolic links that point outside the designated sandbox. The presence of this vulnerability indicates a fundamental gap in input validation and path canonicalization within the utility scripts responsible for copying files into or out of jail contexts.
The technical mechanism behind this exploit relies on the ability of an attacker operating inside a restricted jail environment to create malicious symbolic links. By crafting symlinks that resolve to paths located outside the jail's root directory, such as critical system directories on the host machine or other unrelated jails, the user can manipulate the behavior of administrative tools. When these scripts are executed by privileged users, typically with root privileges, they follow the symlink without verifying its final destination against a whitelist of allowed paths. This lack of strict path validation allows the file copy operation to bypass isolation controls entirely, effectively treating host files as if they were local resources within the jail.
The operational impact of this vulnerability is severe, leading directly to privilege escalation and potential full system compromise. Since the cp.sh, rcp.sh, and jcp.sh commands are often invoked by administrators who possess elevated privileges, an attacker inside a low-privilege jail can leverage these tools to overwrite sensitive host configuration files or exfiltrate confidential data from other jails. This capability undermines the core security principle of least privilege and isolation that jails are designed to provide. An adversary could replace system binaries with malicious versions, install backdoors in startup scripts, or steal cryptographic keys stored on the host, thereby gaining persistent access and control over the underlying infrastructure.
From a threat modeling perspective, this vulnerability aligns with MITRE ATT&CK techniques related to container escape and privilege escalation. Specifically, it mirrors tactics where attackers abuse legitimate administrative tools to move laterally across system boundaries. The ability to write to arbitrary locations on the host filesystem corresponds to persistence mechanisms that allow long-term access even after initial detection attempts. Furthermore, reading sensitive files from other jails or the host environment facilitates reconnaissance and credential harvesting, which are precursors to more advanced attacks such as lateral movement within a networked infrastructure.
Mitigation strategies must focus on both immediate remediation and architectural improvements. The primary solution is to upgrade Bastille to version 1.4.5 or later, where this symlink following issue has been addressed through improved path validation logic. Administrators should also audit their usage of these specific subcommands, ensuring that they are not being used in automated scripts with overly broad permissions unless absolutely necessary. Implementing mandatory access control systems such as SELinux or AppArmor can provide an additional layer of defense by restricting file system operations based on security policies rather than relying solely on application-level checks. Additionally, adopting a principle of least privilege for the accounts executing these commands can limit the blast radius if future vulnerabilities are discovered in similar utilities.