{"id":"CVE-2026-43965","state":"PUBLISHED","title":"Path Traversal in build/packages/packages.toml Allows Arbitrary Directory Deletion","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.","publishedAt":"2026-06-02T13:41:37.421Z","updatedAt":"2026-09-08T01:05:35.928Z","severity":{"score":5.6,"label":"Medium","version":"4.0","vector":"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","source":"EEF"},"assigner":"EEF","products":["Gleam Gleam"],"affected":[{"vendor":"Gleam","product":"Gleam","packageName":"gleam","packageURL":"pkg:software-id/gleam.run/gleam","defaultStatus":"unaffected","versions":[{"version":"0.18.0-rc1","status":"affected","lessThan":"1.17.0","versionType":"semver"}],"cpes":["cpe:2.3:a:gleam-lang:gleam:*:*:*:*:*:*:*:*"],"modules":["compiler-cli"],"programFiles":["compiler-cli/src/dependencies.rs"],"programRoutines":[{"name":"compiler_cli::dependencies::remove_extra_packages"},{"name":"compiler_cli::dependencies::LocalPackages::read_from_disc"},{"name":"compiler_cli::dependencies::LocalPackages::extra_local_packages"}]},{"vendor":"Gleam","product":"Gleam","packageName":"gleam-lang/gleam","packageURL":"pkg:github/gleam-lang/gleam","defaultStatus":"unaffected","versions":[{"version":"0.18.0-rc1","status":"affected","lessThan":"1.17.0","versionType":"semver"},{"version":"ed7aec0484f10d60978b63788c8a6497590855ab","status":"affected","lessThan":"690ca069817bee5f77a28fc3e360627c1da19291","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:gleam-lang:gleam:*:*:*:*:*:*:*:*"],"modules":["compiler-cli"],"programFiles":["compiler-cli/src/dependencies.rs"],"programRoutines":[{"name":"compiler_cli::dependencies::remove_extra_packages"},{"name":"compiler_cli::dependencies::LocalPackages::read_from_disc"},{"name":"compiler_cli::dependencies::LocalPackages::extra_local_packages"}],"repo":"https://github.com/gleam-lang/gleam"},{"vendor":"Gleam","product":"Gleam","packageName":"gleam-lang/gleam","packageURL":"pkg:oci/gleam?repository_url=ghcr.io/gleam-lang","defaultStatus":"unaffected","versions":[{"version":"v0.18.0-rc1-elixir","status":"affected","lessThan":"v1.17.0-elixir","versionType":"other"},{"version":"v0.18.0-rc1-erlang","status":"affected","lessThan":"v1.17.0-erlang","versionType":"other"},{"version":"v0.18.0-rc1-node","status":"affected","lessThan":"v1.17.0-node","versionType":"other"},{"version":"v0.18.0-rc1-node-slim","status":"affected","lessThan":"v1.17.0-node-slim","versionType":"other"},{"version":"v0.18.0-rc1-elixir-slim","status":"affected","lessThan":"v1.17.0-elixir-slim","versionType":"other"},{"version":"v0.18.0-rc1-erlang-slim","status":"affected","lessThan":"v1.17.0-erlang-slim","versionType":"other"},{"version":"v0.18.0-rc1-erlang-alpine","status":"affected","lessThan":"v1.17.0-erlang-alpine","versionType":"other"},{"version":"v0.18.0-rc1-elixir-alpine","status":"affected","lessThan":"v1.17.0-elixir-alpine","versionType":"other"},{"version":"v0.18.0-rc1-node-alpine","status":"affected","lessThan":"v1.17.0-node-alpine","versionType":"other"},{"version":"v0.18.0-rc1-scratch","status":"affected","lessThan":"v1.17.0-scratch","versionType":"other"}],"collectionURL":"https://ghcr.io","cpes":["cpe:2.3:a:gleam-lang:gleam:*:*:*:*:*:*:*:*"],"modules":["compiler-cli"],"programFiles":["compiler-cli/src/dependencies.rs"],"programRoutines":[{"name":"compiler_cli::dependencies::remove_extra_packages"},{"name":"compiler_cli::dependencies::LocalPackages::read_from_disc"},{"name":"compiler_cli::dependencies::LocalPackages::extra_local_packages"}]}],"references":["https://github.com/gleam-lang/gleam/security/advisories/GHSA-jqvf-f6p2-wrv3","https://cna.erlef.org/cves/CVE-2026-43965.html","https://osv.dev/vulnerability/EEF-CVE-2026-43965","https://github.com/gleam-lang/gleam/commit/690ca069817bee5f77a28fc3e360627c1da19291"],"weaknesses":["CWE-22"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43965.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43965","state":"PUBLISHED","datePublished":"2026-06-02T13:41:37.421Z","dateUpdated":"2026-09-08T01:05:35.928Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-05-04T18:23:25.573Z"},"containers":{"cna":{"title":"Path 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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 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