{"id":"CVE-2026-42795","state":"PUBLISHED","title":"Symlink Following in Hex Package Export Allows Embedding Files Outside Project Root","description":"Symlink following vulnerability in Gleam's Hex package export allows files outside the project root to be embedded in the generated package tarball.\n\nThe file collection helpers (gleam_files, native_files, private_files) in compiler-cli/src/fs.rs use follow_links(true) when walking publishable directories such as src/ and priv/. The collected paths are added to the package archive via add_path_to_tar in compiler-cli/src/publish.rs without verifying that the resolved target remains within the project root. A symlink placed under a publishable directory will cause gleam export hex-tarball or gleam publish to embed the contents of the symlink target into the generated Hex package.\n\nAn attacker with write access to the project repository can place a symlink in src/ or priv/ pointing to an arbitrary file. When a maintainer or CI pipeline runs gleam publish or gleam export hex-tarball, local files readable by the publisher (such as secrets, tokens, or SSH keys) are silently embedded into the published package artifact.\n\nThis issue affects Gleam from 0.10.0-rc1 until 1.17.0.","publishedAt":"2026-06-02T13:41:39.527Z","updatedAt":"2026-09-08T01:05:20.790Z","severity":{"score":5.1,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:A/VC:H/VI:N/VA:N/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":"0.10.0-rc1","status":"affected","lessThan":"1.17.0","versionType":"semver"}],"cpes":["cpe:2.3:a:gleam-lang:gleam:*:*:*:*:*:*:*:*"],"modules":["compiler-cli"],"programFiles":["compiler-cli/src/fs.rs","compiler-cli/src/publish.rs"],"programRoutines":[{"name":"compiler_cli::fs::gleam_files"},{"name":"compiler_cli::fs::native_files"},{"name":"compiler_cli::fs::private_files"},{"name":"compiler_cli::publish::project_files"},{"name":"compiler_cli::publish::add_path_to_tar"}]},{"vendor":"Gleam","product":"Gleam","packageName":"gleam-lang/gleam","packageURL":"pkg:github/gleam-lang/gleam","defaultStatus":"unaffected","versions":[{"version":"0.10.0-rc1","status":"affected","lessThan":"1.17.0","versionType":"semver"},{"version":"c82a2d83bd0c06cafdc196820deb3f89a9b3ff7c","status":"affected","lessThan":"6435a5528b9ae0449e2f32be579641ec485f6866","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:gleam-lang:gleam:*:*:*:*:*:*:*:*"],"modules":["compiler-cli"],"programFiles":["compiler-cli/src/fs.rs","compiler-cli/src/publish.rs"],"programRoutines":[{"name":"compiler_cli::fs::gleam_files"},{"name":"compiler_cli::fs::native_files"},{"name":"compiler_cli::fs::private_files"},{"name":"compiler_cli::publish::project_files"},{"name":"compiler_cli::publish::add_path_to_tar"}],"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":"v0.10.0-rc1-elixir","status":"affected","lessThan":"v1.17.0-elixir","versionType":"other"},{"version":"v0.10.0-rc1-erlang","status":"affected","lessThan":"v1.17.0-erlang","versionType":"other"},{"version":"v0.10.0-rc1-node","status":"affected","lessThan":"v1.17.0-node","versionType":"other"},{"version":"v0.10.0-rc1-node-slim","status":"affected","lessThan":"v1.17.0-node-slim","versionType":"other"},{"version":"v0.10.0-rc1-elixir-slim","status":"affected","lessThan":"v1.17.0-elixir-slim","versionType":"other"},{"version":"v0.10.0-rc1-erlang-slim","status":"affected","lessThan":"v1.17.0-erlang-slim","versionType":"other"},{"version":"v0.10.0-rc1-erlang-alpine","status":"affected","lessThan":"v1.17.0-erlang-alpine","versionType":"other"},{"version":"v0.10.0-rc1-elixir-alpine","status":"affected","lessThan":"v1.17.0-elixir-alpine","versionType":"other"},{"version":"v0.10.0-rc1-node-alpine","status":"affected","lessThan":"v1.17.0-node-alpine","versionType":"other"},{"version":"v0.10.0-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/fs.rs","compiler-cli/src/publish.rs"],"programRoutines":[{"name":"compiler_cli::fs::gleam_files"},{"name":"compiler_cli::fs::native_files"},{"name":"compiler_cli::fs::private_files"},{"name":"compiler_cli::publish::project_files"},{"name":"compiler_cli::publish::add_path_to_tar"}]}],"references":["https://github.com/gleam-lang/gleam/security/advisories/GHSA-qhh5-fg4c-8gqc","https://cna.erlef.org/cves/CVE-2026-42795.html","https://osv.dev/vulnerability/EEF-CVE-2026-42795","https://github.com/gleam-lang/gleam/commit/6435a5528b9ae0449e2f32be579641ec485f6866"],"weaknesses":["CWE-59"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/42xxx/CVE-2026-42795.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-42795","state":"PUBLISHED","datePublished":"2026-06-02T13:41:39.527Z","dateUpdated":"2026-09-08T01:05:20.790Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-04-29T18:06:33.251Z"},"containers":{"cna":{"title":"Symlink Following in Hex Package Export Allows Embedding Files Outside Project Root","descriptions":[{"lang":"en","value":"Symlink following vulnerability in Gleam's Hex package export allows files outside the project root to be embedded in the generated package tarball.\n\nThe file collection helpers (gleam_files, native_files, private_files) in compiler-cli/src/fs.rs use follow_links(true) when walking publishable directories such as src/ and priv/. The collected paths are added to the package archive via add_path_to_tar in compiler-cli/src/publish.rs without verifying that the resolved target remains within the project root. A symlink placed under a publishable directory will cause gleam export hex-tarball or gleam publish to embed the contents of the symlink target into the generated Hex package.\n\nAn attacker with write access to the project repository can place a symlink in src/ or priv/ pointing to an arbitrary file. When a maintainer or CI pipeline runs gleam publish or gleam export hex-tarball, local files readable by the publisher (such as secrets, tokens, or SSH keys) are silently embedded into the published package artifact.\n\nThis issue affects Gleam from 0.10.0-rc1 until 1.17.0."}],"affected":[{"vendor":"Gleam","product":"Gleam","packageName":"gleam","packageURL":"pkg:software-id/gleam.run/gleam","defaultStatus":"unaffected","versions":[{"version":"0.10.0-rc1","status":"affected","lessThan":"1.17.0","versionType":"semver"}],"cpes":["cpe:2.3:a:gleam-lang:gleam:*:*:*:*:*:*:*:*"],"modules":["compiler-cli"],"programFiles":["compiler-cli/src/fs.rs","compiler-cli/src/publish.rs"],"programRoutines":[{"name":"compiler_cli::fs::gleam_files"},{"name":"compiler_cli::fs::native_files"},{"name":"compiler_cli::fs::private_files"},{"name":"compiler_cli::publish::project_files"},{"name":"compiler_cli::publish::add_path_to_tar"}]},{"vendor":"Gleam","product":"Gleam","packageName":"gleam-lang/gleam","packageURL":"pkg:github/gleam-lang/gleam","defaultStatus":"unaffected","versions":[{"version":"0.10.0-rc1","status":"affected","lessThan":"1.17.0","versionType":"semver"},{"version":"c82a2d83bd0c06cafdc196820deb3f89a9b3ff7c","status":"affected","lessThan":"6435a5528b9ae0449e2f32be579641ec485f6866","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:gleam-lang:gleam:*:*:*:*:*:*:*:*"],"modules":["compiler-cli"],"programFiles":["compiler-cli/src/fs.rs","compiler-cli/src/publish.rs"],"programRoutines":[{"name":"compiler_cli::fs::gleam_files"},{"name":"compiler_cli::fs::native_files"},{"name":"compiler_cli::fs::private_files"},{"name":"compiler_cli::publish::project_files"},{"name":"compiler_cli::publish::add_path_to_tar"}],"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":"v0.10.0-rc1-elixir","status":"affected","lessThan":"v1.17.0-elixir","versionType":"other"},{"version":"v0.10.0-rc1-erlang","status":"affected","lessThan":"v1.17.0-erlang","versionType":"other"},{"version":"v0.10.0-rc1-node","status":"affected","lessThan":"v1.17.0-node","versionType":"other"},{"version":"v0.10.0-rc1-node-slim","status":"affected","lessThan":"v1.17.0-node-slim","versionType":"other"},{"version":"v0.10.0-rc1-elixir-slim","status":"affected","lessThan":"v1.17.0-elixir-slim","versionType":"other"},{"version":"v0.10.0-rc1-erlang-slim","status":"affected","lessThan":"v1.17.0-erlang-slim","versionType":"other"},{"version":"v0.10.0-rc1-erlang-alpine","status":"affected","lessThan":"v1.17.0-erlang-alpine","versionType":"other"},{"version":"v0.10.0-rc1-elixir-alpine","status":"affected","lessThan":"v1.17.0-elixir-alpine","versionType":"other"},{"version":"v0.10.0-rc1-node-alpine","status":"affected","lessThan":"v1.17.0-node-alpine","versionType":"other"},{"version":"v0.10.0-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/fs.rs","compiler-cli/src/publish.rs"],"programRoutines":[{"name":"compiler_cli::fs::gleam_files"},{"name":"compiler_cli::fs::native_files"},{"name":"compiler_cli::fs::private_files"},{"name":"compiler_cli::publish::project_files"},{"name":"compiler_cli::publish::add_path_to_tar"}]}],"references":[{"url":"https://github.com/gleam-lang/gleam/security/advisories/GHSA-qhh5-fg4c-8gqc","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-42795.html","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-42795","tags":["related"]},{"url":"https://github.com/gleam-lang/gleam/commit/6435a5528b9ae0449e2f32be579641ec485f6866","tags":["patch"]}],"metrics":[{"cvssV4_0":{"attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"LOCAL","baseScore":5.1,"baseSeverity":"MEDIUM","privilegesRequired":"LOW","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"ACTIVE","vectorString":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"NONE"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-59","description":"CWE-59 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<tt>gleam export hex-tarball</tt> on untrusted projects</li><li>Review the contents of <tt>src/</tt> and <tt>priv/</tt> for unexpected symlinks before publishing</li><li>Run publishing commands in a restricted or isolated environment (e.g. containers)</li></ul>"}],"value":"* Avoid running gleam publish or gleam export hex-tarball on untrusted projects\n* Review the contents of src/ and priv/ for unexpected symlinks before publishing\n* Run publishing commands in a restricted or isolated environment (e.g. containers)"}],"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/gleam-lang/gleam/security/advisories/GHSA-qhh5-fg4c-8gqc","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-02T15:04:06.195456Z","id":"CVE-2026-42795","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-02T15:04:35.767Z"}}]}}}