CVE-2026-43965

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine without logging in, but needs a user to act. High risk of service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-06-02 14:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-06 22:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 5.6 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-06-02 14:16 UTC

Last modified

2026-10-06 22:10 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-22 · Path traversal

Record status

Deferred

Attack profile CVSS 4.0 · 5.6

Attack vector

Local

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

Active

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-43965.md and follow it. Check whether this project is affected by CVE-2026-43965. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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