AWS Toolkit for VS Code Leaves CodeCatalyst Tokens Exposed to Local Users
A flaw in the AWS Toolkit allows local attackers to steal cached bearer tokens due to insecure file permissions on shared systems.
Key points
- CVE-2026-107332 affects AWS Toolkit for Visual Studio Code versions prior to 4.10.0
- Cached CodeCatalyst bearer tokens were stored with world-readable permissions
- The vulnerable token files were not deleted after the user session ended
AWS has released a security bulletin addressing CVE-2026-107332, a vulnerability in the AWS Toolkit for Visual Studio Code that exposes cached credentials to local attackers. The issue stems from insecure default file permissions applied to temporary files containing bearer tokens for Amazon CodeCatalyst.
Root cause
The AWS Toolkit for Visual Studio Code is an open-source extension that enables developers to interact with AWS services, including Amazon CodeCatalyst, directly within the Visual Studio Code editor. According to the AWS Security Bulletin published on October 8, 2026, the flaw resides in the CodeCatalyst connection handler.
When a user connected to a CodeCatalyst Dev Environment, the extension saved the user’s bearer token to a local file. The critical error was that this file was created with world-readable permissions, allowing any user or process on the same machine with filesystem access to read the contents. Furthermore, the extension failed to remove the file after the session concluded, leaving the credential exposed indefinitely.
Attack path
An attacker with local access to the victim’s machine could exploit this vulnerability by scanning the filesystem for the cached token file. Because the permissions were set to world-readable, no elevated privileges were required to open and read the file. Once obtained, the attacker could use the bearer token to authenticate as the victim within the CodeCatalyst service. This risk is particularly relevant on shared development machines or systems where multiple users have access to the same operating system environment.
Affected versions
The vulnerability impacts all versions of the AWS Toolkit for Visual Studio Code prior to 4.10.0. Users running any version below this threshold are susceptible to the credential exposure described in bulletin 2026-129-AWS.
Mitigation
- Update the AWS Toolkit for Visual Studio Code to version 4.10.0 or later to resolve the insecure permissions issue.
- Rotate any CodeCatalyst bearer tokens that may have been cached on affected systems before patching.
- Review local filesystem permissions for any remaining temporary credential files and delete them manually if an update is not immediately possible.
What to do and how to stay safe: AWS
- Firewalls cannot stop attacks that originate from inside your network or use allowed ports.
- Antivirus software struggles to detect new exploits that do not yet have a known signature.
- Third-party libraries and plugins often introduce vulnerabilities that the main application vendor cannot fix.
Unpatched software remains a critical vulnerability regardless of your other security measures. Audit your software inventory regularly and apply patches promptly to close known entry points.
Step-by-step guide: Unpatched Software Myths: Why Common Beliefs Fail to Protect You
General security guidance from the BlueTeam Insider newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is CVE-2026-107332?
It is a vulnerability in the AWS Toolkit for Visual Studio Code where cached CodeCatalyst bearer tokens are stored with world-readable permissions.
Which versions of the extension are affected?
All versions of the AWS Toolkit for Visual Studio Code prior to 4.10.0 are impacted by this issue.
Is there a patch available?
Yes, AWS has released version 4.10.0 of the extension to fix the insecure default file permissions and ensure token files are removed after sessions end.
