hexpm hex up to 2.5.1 Shell Hex.Shell.info neutralization

Summaryinfo

A vulnerability classified as critical has been found in hexpm hex up to 2.5.1. Affected by this issue is the function Hex.Shell.info of the component Shell. This manipulation causes neutralization. The identification of this vulnerability is CVE-2026-81856. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in hexpm hex up to 2.5.1. Affected by this vulnerability is the function Hex.Shell.info of the component Shell. The manipulation with an unknown input leads to a neutralization vulnerability. The CWE definition for the vulnerability is CWE-707. The product does not ensure or incorrectly ensures that structured messages or data are well-formed and that certain security properties are met before being read from an upstream component or sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Improper Neutralization of Escape, Meta, or Control Sequences vulnerability in hexpm hex allows a malicious package publisher or a hostile repository server to inject terminal control sequences into the output of Mix tasks. Hex prints strings supplied by the package repository and the documentation search service straight to the terminal through Hex.Shell.info/1 and Hex.Shell.error/1, neutralizing no control characters. Affected sinks span package metadata and configuration snippets in mix hex.info, search results in mix hex.package search and mix hex.search, owner and organization listings, publish and sponsor URLs, the authenticated username in mix hex.user, policy identities in mix hex.policy, and API error bodies rendered by Hex.Utils.print_error_result/1. A malicious package can embed ANSI escape sequences (cursor movement, line erase, carriage returns, OSC 52 clipboard writes) or Unicode bidirectional overrides in any of those fields, so the bytes reach the terminal unchanged, forging displayed URLs, package descriptions and suggested commands, concealing real output, or writing to the clipboard. No authentication or privileged position is required; only publishing a package. This issue affects hex: from 0.0.1 before 2.5.2.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-81856 since 08/31/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

Upgrading to version 2.5.2 eliminates this vulnerability.

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Productinfo

Vendor

• hexpm

Name

• hex

Version

• 2.5.0
• 2.5.1

Website

• Product: https://github.com/hexpm/hex/

CPE 2.3info

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CPE 2.2info

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