Weakness Type (CWE)

CWE-22 — CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CAPEC

CVSS 4.0 Score

5.6

MEDIUM

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Vulnerability description

Path traversal vulnerability in Gleam's dependency management allows arbitrary directory deletion via malicious build/packages/packages.toml content.

Package keys read from build/packages/packages.toml by LocalPackages::read_from_disc are passed without validation to paths.build_packages_package(), which constructs a filesystem path by joining the project build directory with the attacker-controlled key. The resulting path is then passed to fs::delete_directory (which calls remove_dir_all). No check is performed to ensure the path remains within the intended build/packages/ directory. Both absolute paths and relative traversal sequences (e.g. ../) are accepted as package keys, allowing deletion of arbitrary directories.

An attacker who can cause a victim to run gleam deps download on a project containing a malicious build/packages/packages.toml (e.g. by committing the normally-gitignored file to a repository) can cause arbitrary directories on the victim's system to be recursively deleted.

This issue affects Gleam from 0.18.0-rc1 until 1.17.0.

Affected

pkg:sid/gleam.run/gleam

Module Source File Routine
compiler-cli compiler-cli/src/dependencies.rs compiler_cli::dependencies::remove_extra_packages
compiler_cli::dependencies::LocalPackages::read_from_disc
compiler_cli::dependencies::LocalPackages::extra_local_packages
Status Type Version Changes / Fixed in
affected semver ⓘ 0.18.0-rc1 < 1.17.0

pkg:github/gleam-lang/gleam

Module Source File Routine
compiler-cli compiler-cli/src/dependencies.rs compiler_cli::dependencies::remove_extra_packages
compiler_cli::dependencies::LocalPackages::read_from_disc
compiler_cli::dependencies::LocalPackages::extra_local_packages
Status Type Version Changes / Fixed in
affected semver ⓘ 0.18.0-rc1 < 1.17.0
affected git ⓘ ed7aec0484 < 690ca06981

pkg:oci/gleam

Module Source File Routine
compiler-cli compiler-cli/src/dependencies.rs compiler_cli::dependencies::remove_extra_packages
compiler_cli::dependencies::LocalPackages::read_from_disc
compiler_cli::dependencies::LocalPackages::extra_local_packages
Status Type Version Changes / Fixed in
affected other v0.18.0-rc1-elixir < v1.17.0-elixir
affected other v0.18.0-rc1-erlang < v1.17.0-erlang
affected other v0.18.0-rc1-node < v1.17.0-node
affected other v0.18.0-rc1-node-slim < v1.17.0-node-slim
affected other v0.18.0-rc1-elixir-slim < v1.17.0-elixir-slim
affected other v0.18.0-rc1-erlang-slim < v1.17.0-erlang-slim
affected other v0.18.0-rc1-erlang-alpine < v1.17.0-erlang-alpine
affected other v0.18.0-rc1-elixir-alpine < v1.17.0-elixir-alpine
affected other v0.18.0-rc1-node-alpine < v1.17.0-node-alpine
affected other v0.18.0-rc1-scratch < v1.17.0-scratch

References

Credits

  • Finder: Aly (spect3r1)
  • Finder: Abdelrahman Ahmed Aboelkasem (0x2face)
  • Remediation developer: Louis Pilfold
  • Analyst: Jonatan Männchen / EEF

CVE record as JSON:  GET /cves/CVE-2026-43965.json
OSV record as JSON:  GET /osv/EEF-CVE-2026-43965.json