Path Traversal in build/packages/packages.toml Allows Arbitrary Directory Deletion_CVE-2026-43965

5.6 / 10

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

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.

Basic Information

ID CVE-2026-43965

Source EEF

Published Jun 2, 2026 at 13:41

Affected Product

Vendor Gleam

Product Gleam

Version 0.18.0-rc1

Affected Versions Gleam Gleam 0.18.0-rc1
Gleam Gleam 0.18.0-rc1
Gleam Gleam ed7aec0484f10d60978b63788c8a6497590855ab
Gleam Gleam v0.18.0-rc1-elixir
Gleam Gleam v0.18.0-rc1-erlang
Gleam Gleam v0.18.0-rc1-node
Gleam Gleam v0.18.0-rc1-node-slim
Gleam Gleam v0.18.0-rc1-elixir-slim
Gleam Gleam v0.18.0-rc1-erlang-slim
Gleam Gleam v0.18.0-rc1-erlang-alpine
Gleam Gleam v0.18.0-rc1-elixir-alpine
Gleam Gleam v0.18.0-rc1-node-alpine
Gleam Gleam v0.18.0-rc1-scratch

CWE Classification

CWE-22

References

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    "description": "Path traversal vulnerability in Gleam's dependency management allows arbitrary directory deletion via malicious build/packages/packages.toml content.\n\nPackage 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.\n\nAn 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.\n\nThis issue affects Gleam from 0.18.0-rc1 until 1.17.0.",
    "published": "2026-06-02T13:41:37.421Z",
    "modified": "2026-06-02T13:41:37.421Z",
    "type": "cve",
    "title": "Path Traversal in build/packages/packages.toml Allows Arbitrary Directory Deletion",
    "source": "EEF",
    "references": "https://github.com/gleam-lang/gleam/security/advisories/GHSA-jqvf-f6p2-wrv3\nhttps://cna.erlef.org/cves/CVE-2026-43965.html\nhttps://osv.dev/vulnerability/EEF-CVE-2026-43965\nhttps://github.com/gleam-lang/gleam/commit/690ca069817bee5f77a28fc3e360627c1da19291",
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