CVE-2026-81684 in openssl_encrypt
Summary
by MITRE • 08/27/2026
In openssl_encrypt (pip package openssl-encrypt) versions <= 1.4.8, the desktop GUI passes the steganography password to the CLI child process on the command line via the --stego-password argument (on both encrypt and decrypt paths) instead of via an environment variable as done for the main password. Any local user can read the steganography password from /proc/<pid>/cmdline for the lifetime of the subprocess. Fixed in 1.4.9.
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified in openssl-encrypt versions up to and including 1.4.8 represents a critical failure in secure credential handling within desktop applications that interface with command-line utilities. The core technical flaw lies in the method used by the graphical user interface to transmit sensitive steganography passwords to child processes spawned via the Command Line Interface. Instead of utilizing environment variables, which are generally considered more secure for passing secrets between parent and child processes as they do not appear in process listings or system logs, the application passes the password directly through command-line arguments using the --stego-password flag. This architectural decision exposes sensitive data to local privilege escalation vectors that would otherwise be mitigated by proper isolation techniques.
From a technical perspective, operating systems such as Linux and macOS expose the full command line of every running process through virtual file system interfaces like /proc/<pid>/cmdline on Unix-like systems or via task information queries in Windows. Any user account with read access to these files can inspect the arguments passed to any other process owned by that user or, depending on kernel configuration settings such as ptrace permissions and procfs visibility restrictions, potentially even processes belonging to other users if those protections are not strictly enforced. Consequently, a local attacker who gains access to the system can monitor the execution of openssl-encrypt commands in real-time or retrospectively analyze process history files to extract the plaintext steganography password. This exposure persists for the entire duration that the child subprocess remains active, providing a wide window of opportunity for exploitation by any malicious script or user on the same machine.
The operational impact of this vulnerability is severe due to the nature of the protected data. Steganography passwords are typically used to hide sensitive information within digital media files such as images or audio clips. If an attacker retrieves these passwords, they can decrypt and access the hidden content without detection by the legitimate user who believes their data remains concealed. This undermines the fundamental security guarantee provided by steganographic tools, which is plausible deniability combined with confidentiality. The risk extends beyond simple password theft; if the encrypted payload contains credentials for other systems or sensitive corporate intelligence, the breach could lead to further compromise of broader infrastructure. Furthermore, because this flaw affects both encryption and decryption paths, it compromises data integrity during creation as well as access during retrieval.
This vulnerability aligns with CWE-78 Improper Neutralization of Special Elements used in an OS Command, specifically regarding the leakage of sensitive information through command-line arguments rather than injection per se, but more accurately maps to CWE-259 Use of Hard-coded Passwords or CWE-312 Cleartext Storage of Sensitive Information. In terms of adversary behavior, this flaw facilitates Local Privilege Escalation and Credential Access as defined in the MITRE ATT&CK framework under techniques such as T1087 Account Discovery or more specifically T1552 Unsecured Credentials where attackers gather credentials from local system sources. The attack vector is classified as Local with Low complexity, requiring only that an attacker has a shell account on the target machine to execute simple commands against /proc entries.
To mitigate this vulnerability and prevent similar issues in future software development, applications must avoid passing sensitive secrets via command-line arguments entirely. Developers should implement secure inter-process communication mechanisms such as environment variables for non-sensitive configuration or, preferably, temporary files with restricted permissions that are deleted immediately after use, or memory-mapped shared segments where appropriate. For the openssl-encrypt package specifically, upgrading to version 1.4.9 resolves this issue by correcting the transmission method of the steganography password. System administrators should ensure all instances of affected software are updated and consider implementing file integrity monitoring on /proc entries if feasible within their security posture, although updating the application remains the primary remediation step.