Improper Neutralization of Escape, Meta, or Control Sequences vulnerability in ash-project usage_rules allows a malicious package publisher to inject terminal control sequences into the output of mix usage_rules.search_docs. mix usage_r…

Overview

Improper Neutralization of Escape, Meta, or Control Sequences vulnerability in ash-project usage_rules allows a malicious package publisher to inject terminal control sequences into the output of mix usage_rules.search_docs.

mix usage_rules.search_docs searches Hex documentation through search.hexdocs.pm, which indexes the documentation of every published package, and prints the matching results (title, package, type, doc reference, and highlighted snippets) to the terminal. The formatter in Mix.Tasks.UsageRules.SearchDocs interpolated those publisher-controlled fields verbatim, neutralizing no terminal control characters; the only transform it applied adds escape sequences rather than removing them. A malicious package can embed ANSI terminal escape sequences (cursor movement, line erase, carriage returns, OSC 52 clipboard writes) in its indexed documentation, so when a developer runs a search that surfaces those docs the sequences reach the terminal unchanged — forging the displayed hexdocs URL or a suggested command, hiding text, or writing to the clipboard. No authentication or privileged position is required; only publishing a package.

This issue affects usage_rules: from 0.1.18 before 1.2.8.

Remediation

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