Description
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in erlang rebar3 allows a malicious package publisher to delete a directory outside the project's _build directory and extract package files into it when a developer fetches dependencies.

A package release's dependencies in a Hex registry carry an app field that names the dependency's OTP application. rebar3 uses this field as the dependency's name without validating it (rebar_packages:parse_deps/1) and builds the dependency's directory from that name (rebar_app_utils:dep_to_app/7). rebar_fetch:download_source_online/2 deletes that directory with rm -rf and moves the fetched package into it. 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. When a project depends on such a release directly or transitively, rebar3 get-deps deletes the directory the name resolves to and writes the dependency's files there. This happens before the dependency's own rebar.config.script is evaluated, and get-deps compiles nothing.

This issue affects rebar3: from 3.7.0-rc1 before 3.27.2.
Published: 2026-10-12
Score: 7.5 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

Vendor Solution

Upgrade rebar3 to 3.27.2 or later, for example with rebar3 local upgrade. rebar3 then fails with an error when a dependency's name, including the app name a package release gives a dependency, isn't a letter followed by letters, digits, _ and -.

Tracking

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Advisories

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History

Mon, 12 Oct 2026 16:00:00 +0000

Type Values Removed Values Added
Description Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in erlang rebar3 allows a malicious package publisher to delete a directory outside the project's _build directory and extract package files into it when a developer fetches dependencies. A package release's dependencies in a Hex registry carry an app field that names the dependency's OTP application. rebar3 uses this field as the dependency's name without validating it (rebar_packages:parse_deps/1) and builds the dependency's directory from that name (rebar_app_utils:dep_to_app/7). rebar_fetch:download_source_online/2 deletes that directory with rm -rf and moves the fetched package into it. 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. When a project depends on such a release directly or transitively, rebar3 get-deps deletes the directory the name resolves to and writes the dependency's files there. This happens before the dependency's own rebar.config.script is evaluated, and get-deps compiles nothing. This issue affects rebar3: from 3.7.0-rc1 before 3.27.2.
Title Path traversal in rebar3 via unvalidated dependency app names
First Time appeared Erlang
Erlang rebar3
Weaknesses CWE-22
CPEs cpe:2.3:a:erlang:rebar3:*:*:*:*:*:*:*:*
Vendors & Products Erlang
Erlang rebar3
References
Metrics cvssV4_0

{'score': 7.5, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: EEF

Published:

Updated: 2026-10-12T15:43:57.636Z

Reserved: 2026-10-06T08:45:01.521Z

Link: CVE-2026-103060

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-12T16:17:00.873

Modified: 2026-10-12T16:17:00.873

Link: CVE-2026-103060

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-22

    Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')