Bulletin ID: HCSEC-2026-29
Affected Products / Versions: Packer 1.7.0 up to 1.15.4; fixed in Packer 1.16.0
Publication Date: August 17, 2026
Summary
Packer up to 1.15.4 is vulnerable to an issue in the third-party plugin installer that may allow unintended file system modification and could lead to code execution. A user who installs a plugin from a malicious or compromised source may be affected. This vulnerability (CVE-2026-19589) is fixed in Packer 1.16.0.
Background
Packer supports third-party plugins that can be installed directly from GitHub-hosted releases using packer init or packer plugins install. During installation, Packer downloads the plugin archive and checksum file from the plugin’s release, verifies the checksum, and writes the plugin binary to a local plugin directory for subsequent use in builds.
Details
Packer did not sufficiently constrain where files could be written during plugin archive extraction. A malicious or compromised plugin release could supply a crafted archive that, when extracted, places files outside the intended plugin directory. This issue may lead to code execution on the machine running the install. This issue affects users who install third-party plugins from a malicious or compromised source using packer init or packer plugins install.
Remediation
Customers should evaluate the risk associated with this issue and consider upgrading to Packer 1.16.0.
Acknowledgement
This issue was reported to HashiCorp by George Chen.
We deeply appreciate any effort to coordinate disclosure of security vulnerabilities. For information about security at HashiCorp and the reporting of security vulnerabilities, please see https://hashicorp.com/security.