Bug 2549857 (CVE-2026-103061)

Summary: CVE-2026-103061 gleam: gleam: Arbitrary directory deletion via path traversal in package metadata
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
Version: unspecifiedCC: gotiwari, jhorak, mvyas, rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in gleam. When downloading dependencies, the build tool uses the application name from package metadata to determine the build directory path without validating it. A malicious package publisher can supply path traversal sequences or an absolute path, causing arbitrary directories on the developer's system to be deleted if the package fails to compile during a build operation.
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Description OSIDB Bzimport 2026-10-12 18:42:06 UTC
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in gleam-lang gleam allows a malicious package publisher to delete a directory outside the project's build directory when a developer builds a project.

A Hex package release's metadata carries an app field with the release's OTP application name. Gleam reads this field from the hex.pm release API when it downloads dependencies and uses it as the package's build directory name without validating it (hex_manifest_package in compiler-cli/src/dependencies.rs, ProjectPaths::build_directory_for_package). When a dependency fails to compile, Gleam deletes that directory with remove_dir_all. hex.pm didn't restrict the field to a directory name before 2026-10-12, so a publisher could set it to a value such as ../../../../target or an absolute path. When a project depends on such a release directly or transitively and the release fails to compile, gleam build, gleam check, gleam run, gleam test or gleam export deletes the directory the name resolves to. For a pure Gleam package no publisher code runs.

This issue affects gleam: from 0.32.4 before 1.19.2.