CVE-2026-97024 in Red Hat
Summary
by MITRE • 09/29/2026
A path traversal vulnerability in Flatpak's handling of the files/etc directory during app deployment allows a malicious Flatpak app to cause certain host system files (such as passwd, group, machine-id, or resolv.conf) to be emptied or replaced with a symlink when the app is installed or upgraded. In system-wide installations, the write is performed as root.
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability identified in Flatpak represents a critical path traversal flaw within the application deployment mechanism, specifically targeting the handling of files located in the etc directory on the host operating system. This security defect allows a malicious or compromised Flatpak application to manipulate sensitive configuration and identity files during installation or upgrade processes. The core technical issue stems from insufficient validation of file paths when deploying content intended for the /etc directory. Instead of strictly isolating writes within an isolated sandboxed environment, the deployment logic permits relative path traversal sequences that escape the designated scope. This allows the application to target absolute system-critical files such as passwd, group, machine-id, and resolv.conf. By exploiting this flaw, an attacker can cause these host system files to be emptied or replaced with symbolic links pointing to arbitrary locations on the filesystem.
The operational impact of this vulnerability is severe due to its potential for privilege escalation and system compromise. In system-wide installations, which are common in enterprise environments where Flatpak applications are deployed for all users without individual sandboxing restrictions, the write operations are executed with root privileges. This means that a malicious app can effectively overwrite or destroy critical authentication databases like passwd and group, potentially locking out legitimate users or creating unauthorized administrative accounts if combined with other exploits. Furthermore, replacing resolv.conf with a symlink allows an attacker to redirect DNS queries, facilitating man-in-the-middle attacks or phishing campaigns by resolving domain names to malicious IP addresses. The modification of machine-id can also disrupt system identification mechanisms used for licensing, logging, and security auditing, leading to significant operational instability and forensic challenges.
From a classification perspective, this vulnerability aligns with CWE-22: Improper Limitation of a Pathname to a Restricted Directory, as it involves accessing files outside the intended scope through path manipulation. Additionally, because the attack vector relies on user interaction such installing or upgrading an application, it relates to CWE-94: Improper Control of Generation of Code Command Injection in contexts where code execution might follow file system modifications. In terms of adversary tactics, this behavior corresponds to ATT&CK technique T1562.001: Impair Defenses: Disable or Modify Tools, specifically by modifying configuration files that support security monitoring and access control mechanisms like PAM (Pluggable Authentication Modules) which relies on the passwd and group files.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. Users should immediately update Flatpak to a version where this path traversal issue has been patched, ensuring that the deployment engine strictly validates all file paths against an allowlist of permitted directories within the sandboxed environment rather than relying solely on directory boundaries which can be bypassed via symlinks or relative paths. System administrators deploying applications system-wide should review their security policies and consider restricting write permissions to /etc for untrusted third-party Flatpak apps, even if they are signed, as a defense-in-depth measure. Furthermore, implementing mandatory access control systems such as SELinux or AppArmor can provide an additional layer of protection by enforcing strict file system access rules that prevent applications from modifying critical host configuration files regardless of the application's internal logic flaws. Regular auditing of installed Flatpak apps and monitoring for unexpected changes in /etc directory permissions or contents is also recommended to detect potential exploitation attempts early.