Weakness Type (CWE)

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

CAPEC

CVSS 4.0 Score

8.3

HIGH

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

Vulnerability description

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.

Affected

pkg:sid/gleam.run/gleam

Module Source File Routine
compiler-core compiler-core/src/config.rs compiler_core::config::dependencies_map::deserialize
compiler-core/src/manifest.rs compiler_core::config::package_name::deserialize
Status Type Version Changes / Fixed in
affected semver ⓘ 1.9.0-rc1
  • unaffected at 1.15.4

pkg:github/gleam-lang/gleam

Module Source File Routine
compiler-core compiler-core/src/config.rs compiler_core::config::dependencies_map::deserialize
compiler-core/src/manifest.rs compiler_core::config::package_name::deserialize
Status Type Version Changes / Fixed in
affected semver ⓘ 1.9.0-rc1
  • unaffected at 1.15.4
affected git ⓘ a4fde22445

pkg:oci/gleam

Module Source File Routine
compiler-core compiler-core/src/config.rs compiler_core::config::dependencies_map::deserialize
compiler-core/src/manifest.rs compiler_core::config::package_name::deserialize
Status Type Version Changes / Fixed in
affected other v1.9.0-rc1-elixir < v1.15.4-elixir
affected other v1.9.0-rc1-erlang < v1.15.4-erlang
affected other v1.9.0-rc1-node < v1.15.4-node
affected other v1.9.0-rc1-node-slim < v1.15.4-node-slim
affected other v1.9.0-rc1-elixir-slim < v1.15.4-elixir-slim
affected other v1.9.0-rc1-erlang-slim < v1.15.4-erlang-slim
affected other v1.9.0-rc1-erlang-alpine < v1.15.4-erlang-alpine
affected other v1.9.0-rc1-elixir-alpine < v1.15.4-elixir-alpine
affected other v1.9.0-rc1-node-alpine < v1.15.4-node-alpine
affected other v1.9.0-rc1-scratch < v1.15.4-scratch

Configurations

The project must use git-based dependencies (direct or transitive), or the victim must run gleam deps download on a repository with a malicious manifest.toml lockfile. Projects that exclusively use Hex dependencies and do not clone untrusted repositories are not affected.

Projects that exclusively use trusted or personally controlled git dependencies, or dependencies pinned to verified commit SHAs, are not exposed.

Workarounds

  • Avoid using untrusted git dependencies, especially without pinning to a specific commit SHA
  • Review dependency trees carefully, including transitive git dependencies
  • Run dependency resolution commands in a restricted or isolated environment (e.g. containers)

Solutions

Upgrade to Gleam 1.15.4 or later.

Both patches must be applied: the original incomplete fix (1aa5d8e594, backported as 55bb36e6d7febfbbc48c4d001e0ae13eb0312d78 to 1.15) and the follow-up fix (2dc0467f82, backported as 92aae3913570e8d8962f6399404777d313045bfa to 1.15). Gleam 1.15.4 includes both.

References

Credits

  • Remediation developer: John Downey
  • Analyst: Louis Pilfold
  • Coordinator: Jonatan Männchen / EEF

CVE record as JSON:  GET /cves/CVE-2026-32146.json
OSV record as JSON:  GET /osv/EEF-CVE-2026-32146.json