---
id: CVE-2026-42795
title: >-
  Symlink following vulnerability in Gleam's Hex package export allows files
  outside the project root to be embedded in the generated package tarball.


  The file collection helpers (gleam_files, native_files, private_files) in
  compiler-cli/…
summary: >-
  Symlink following vulnerability in Gleam's Hex package export allows files
  outside the project root to be embedded in the generated package tarball.


  The file collection helpers (gleam_files, native_files, private_files) in
  compiler-cli/…
severity: medium
cvss: 5.1
cvssVector: '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'
cwe:
  - CWE-59
vendor: Gleam
product: gleam
affected:
  - gleam >= 0.10.0-rc1 < 1.17.0
  - gleam-lang/gleam >= 0.10.0-rc1 < 1.17.0
  - >-
    gleam-lang/gleam >= c82a2d83bd0c06cafdc196820deb3f89a9b3ff7c <
    6435a5528b9ae0449e2f32be579641ec485f6866
  - gleam-lang/gleam >= v0.10.0-rc1-elixir < v1.17.0-elixir
  - gleam-lang/gleam >= v0.10.0-rc1-erlang < v1.17.0-erlang
  - gleam-lang/gleam >= v0.10.0-rc1-node < v1.17.0-node
  - gleam-lang/gleam >= v0.10.0-rc1-node-slim < v1.17.0-node-slim
  - gleam-lang/gleam >= v0.10.0-rc1-elixir-slim < v1.17.0-elixir-slim
  - gleam-lang/gleam >= v0.10.0-rc1-erlang-slim < v1.17.0-erlang-slim
  - gleam-lang/gleam >= v0.10.0-rc1-erlang-alpine < v1.17.0-erlang-alpine
  - gleam-lang/gleam >= v0.10.0-rc1-elixir-alpine < v1.17.0-elixir-alpine
  - gleam-lang/gleam >= v0.10.0-rc1-node-alpine < v1.17.0-node-alpine
  - gleam-lang/gleam >= v0.10.0-rc1-scratch < v1.17.0-scratch
published: '2026-06-02'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T01:17:30.483'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42795'
references:
  - url: 'https://cna.erlef.org/cves/CVE-2026-42795.html'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/gleam-lang/gleam/commit/6435a5528b9ae0449e2f32be579641ec485f6866
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/gleam-lang/gleam/security/advisories/GHSA-qhh5-fg4c-8gqc
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-42795'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/gleam-lang/gleam/security/advisories/GHSA-qhh5-fg4c-8gqc
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-06-02T15:04:06.195456Z'
cvssSource: cna
epss: 0.00167
epssPercentile: 0.05272
ingestedAt: '2026-09-08T13:33:24.799Z'
---

## Overview

Symlink following vulnerability in Gleam's Hex package export allows files outside the project root to be embedded in the generated package tarball.

The 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.

An 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.

This issue affects Gleam from 0.10.0-rc1 until 1.17.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.