Gleam up to 1.15.3/1.16.0-rc1 path traversal

Summaryinfo

A vulnerability identified as critical has been detected in Gleam up to 1.15.3/1.16.0-rc1. This impacts an unknown function. The manipulation leads to path traversal. This vulnerability is documented as CVE-2026-32146. The attack needs to be performed locally. There is not any exploit available. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability was found in Gleam up to 1.15.3/1.16.0-rc1 and classified as critical. This issue affects some unknown functionality. The manipulation with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Improper path validation vulnerability in the Gleam compiler's handling of git dependencies allows arbitrary file system modification during dependency download. Dependency names from gleam.toml and manifest.toml are incorporated into filesystem paths without sufficient validation or confinement to the intended dependency directory, allowing attacker-controlled paths (via relative traversal such as ../ or absolute paths) to target filesystem locations outside that directory. When resolving git dependencies (e.g. via gleam deps download), the computed path is used for filesystem operations including directory deletion and creation. This vulnerability occurs during the dependency resolution and download phase, which is generally expected to be limited to fetching and preparing dependencies within a confined directory. A malicious direct or transitive git dependency can exploit this issue to delete and overwrite arbitrary directories outside the intended dependency directory, including attacker-chosen absolute paths, potentially causing data loss. In some environments, this may be further leveraged to achieve code execution, for example by overwriting git hooks or shell configuration files. This issue affects Gleam from 1.9.0-rc1 until 1.15.4.

The weakness was released by Louis Pilfold as GHSA-vq5j-55vx-wq8j. The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-32146 since 03/10/2026. The exploitation is known to be easy. An attack has to be approached locally. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

Applying the patch 1aa5d8e594b0aa240bb213fce6ee19c65e6d5bcf is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-21680). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Gleam

Version

• 1.15.0
• 1.15.1
• 1.15.2
• 1.15.3
• 1.16.0-rc1

License

• open-source

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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