CVE-2026-32685

Summary

Path traversal vulnerability in Gleam's handling of custom documentation pages allows arbitrary file read and file write outside the intended documentation output directory.

The documentation.pages entries from gleam.toml are incorporated into filesystem paths without sufficient validation or confinement to the intended project and documentation output directories. The documentation.pages[].path field can be used to write generated documentation files outside the intended build/dev/docs/<package>/ output directory. The documentation.pages[].source field can be used to read files outside the project directory and embed their contents into generated documentation output.

An attacker who can convince a victim to run gleam docs build on an untrusted project, or with untrusted gleam.toml content, can cause local files readable by the victim to be included in generated documentation artifacts, and can cause generated documentation files to be written outside the intended docs output directory.

This issue affects Gleam from 1.16.0 until 1.17.0.

Affected Software

VendorProductVersion RangeStatus
GleamGleam1.16.0 < 1.17.0affected
GleamGleam1.16.0 < 1.17.0affected
GleamGleam61ed8deb6572b5591ad17d6302c1a38607522f16 < 81570611906b6b0039c948037094d09a68700f3aaffected
GleamGleamv1.16.0-elixir < v1.17.0-elixiraffected
GleamGleamv1.16.0-erlang < v1.17.0-erlangaffected
GleamGleamv1.16.0-node < v1.17.0-nodeaffected
GleamGleamv1.16.0-node-slim < v1.17.0-node-slimaffected
GleamGleamv1.16.0-elixir-slim < v1.17.0-elixir-slimaffected
GleamGleamv1.16.0-erlang-slim < v1.17.0-erlang-slimaffected
GleamGleamv1.16.0-erlang-alpine < v1.17.0-erlang-alpineaffected
GleamGleamv1.16.0-elixir-alpine < v1.17.0-elixir-alpineaffected
GleamGleamv1.16.0-node-alpine < v1.17.0-node-alpineaffected
GleamGleamv1.16.0-scratch < v1.17.0-scratchaffected

Weaknesses

  • CWE-22: CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Workarounds

  • Avoid running gleam docs build on untrusted projects
  • Review documentation.pages entries in gleam.toml before generating documentation
  • Run documentation generation in a restricted or isolated environment (e.g. containers)

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

Additional References

References