VulnerabilityDeferred

CVE-2026-43965

Path traversal vulnerability in Gleam's dependency management allows arbitrary directory deletion via malicious build/packages/packages.toml content.

MEDIUM 5.6EPSS 0.23%

Does this matter?

Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 4.0: 5.6 MEDIUMCVSS:4.0/AV:L/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/M
EPSS: 0.23% probability · 14th percentile
CISA KEV: Not listed
Weakness: CWE-22
Source: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.