CVE-2026-103061

5.9Medium

Published 12 Oct 2026 · NVD status: Deferred · AI triage by gemini-3.8-flash

5.9Medium

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Active
Impact: High impact on availability
Weakness: CWE-22

Impact

A malicious Hex package publisher can delete arbitrary directories on a developer's machine outside the project build directory. This triggers when building, checking, or testing a project that depends directly or transitively on the malicious package and compilation fails.

Root cause

Gleam uses the unvalidated OTP application name from Hex release metadata as a directory path, calling remove_dir_all on it when a dependency build fails.

Affected systems

Gleam 0.32.4 through versions before 1.19.2

CVSS v4.0 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Fix & remediation

Upgrade Gleam to version 1.19.2 or later. If upgrading immediately is not possible, do not pull or build untrusted Hex dependencies.

shell

$ gleam --version

AI-suggested. Run it in staging first and check it against the vendor advisory. Why?

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NVD description

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in gleam-lang gleam allows a malicious package publisher to delete a directory outside the project's build directory when a developer builds a project. A Hex package release's metadata carries an app field with the release's OTP application name. Gleam reads this field from the hex.pm release API when it downloads dependencies and uses it as the package's build directory name without validating it (hex_manifest_package in compiler-cli/src/dependencies.rs, ProjectPaths::build_directory_for_package). When a dependency fails to compile, Gleam deletes that directory with remove_dir_all. hex.pm didn't restrict the field to a directory name before 2026-10-12, so a publisher could set it to a value such as ../../../../target or an absolute path. When a project depends on such a release directly or transitively and the release fails to compile, gleam build, gleam check, gleam run, gleam test or gleam export deletes the directory the name resolves to. For a pure Gleam package no publisher code runs. This issue affects gleam: from 0.32.4 before 1.19.2.

References

Source: nvd.nist.gov/vuln/detail/CVE-2026-103061