CVE-2026-81838 in diagram-as-code
Summary
by MITRE • 08/27/2026
A relative path traversal issue in the zip extraction functionality in AWS diagram-as-code (awsdac) in versions 0.10 through 0.23 can allow a third party to write arbitrary files to the local filesystem via crafted zip entry names containing path traversal sequences. This could allow the third party to perform inappropriate actions in the diagram bundle.
To remediate this issue, users should upgrade to the version 0.24 or later.
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified as a relative path traversal flaw within AWS Diagram-as-Code (awsdac) versions 0.10 through 0.23 represents a critical security deficiency in how archive files are processed during diagram generation. This issue specifically affects the zip extraction functionality, which is designed to parse bundle files containing infrastructure definitions and visual layout instructions. When users provide a crafted zip file as input for generating AWS architecture diagrams, the application fails to adequately sanitize or validate the internal paths of entries contained within the archive. Consequently, an attacker who controls the content of the diagram bundle can exploit this lack of validation by embedding path traversal sequences, such as dot-dot-slash characters, into the names of individual zip entries.
From a technical perspective, the core flaw lies in the absence of robust normalization and boundary checks before writing extracted files to the local file system. Standard secure coding practices dictate that any external input used for file operations must be strictly validated against directory traversal patterns. In this case, the software directly maps the internal path strings from the zip archive to filesystem paths without ensuring they remain within the intended output directory or do not escape it via relative navigation commands. This allows a third party to manipulate the destination of written files by specifying parent directories in the entry names. The vulnerability is classified under CWE-22, which covers Improper Limitation of a Pathname to a Restricted Directory, highlighting the failure to restrict file access to an expected location.
The operational impact of this vulnerability extends beyond simple data corruption or denial of service. By successfully writing arbitrary files to locations outside the intended extraction directory, an attacker can overwrite critical system configuration files, inject malicious scripts into executable directories, or place web shells in accessible web roots if the target environment serves those paths. This capability effectively leads to Remote Code Execution (RCE) depending on the context and permissions of the user running the awsdac application. The ability to write arbitrary files disrupts the integrity of the host system and can serve as a foothold for further lateral movement within an organization's infrastructure. In terms of threat modeling, this aligns with MITRE ATT&CK techniques related to Command and Scripting Interpreter abuse or File Manipulation, where adversaries modify existing system software to maintain persistence or execute unauthorized commands.
Mitigation strategies must prioritize immediate remediation through version upgrades as well as defensive coding practices for future development. The primary recommendation is to upgrade awsdac to version 0.24 or later, which includes patches that properly sanitize zip entry paths and prevent directory traversal attacks. For environments where upgrading is not immediately feasible, administrators should implement strict input validation on any diagram bundles received from untrusted sources. This involves validating file extensions, scanning archive contents for suspicious path patterns before extraction, and ensuring the application runs with minimal privileges to limit the potential damage of a successful exploit. Additionally, organizations should adopt secure software development lifecycle practices that include static analysis tools capable of detecting path traversal vulnerabilities during the coding phase to prevent similar issues in other applications handling user-supplied archives.