CVE-2026-81856

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.

• CWE-150

• https://cna.erlef.org/cves/CVE-2026-81856.html
• https://github.com/hexpm/hex/commit/211303e3f68f5d3ce06450c1ff1a7a770a9ab236
• https://github.com/hexpm/hex/commit/dd3305ddf0032f6d0b468fd40dbbc3072bfcb8b8
• https://github.com/hexpm/hex/security/advisories/GHSA-fpmj-3cxg-p766
• https://osv.dev/vulnerability/EEF-CVE-2026-81856

Published

Oct 12, 2026

Last Modified

Oct 16, 2026

Status

Deferred

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-81849Improper limitation of a pathname to a restricted directory …8.8
• CVE-2026-8185A security vulnerability has been detected in UGREEN CM933 1…6.3
• CVE-2026-81851A heap-based buffer overflow vulnerability in Fireware OS's …6.9
• CVE-2026-81852Use of Insufficiently Random Values vulnerability in ash-pro…2.1
• CVE-2026-81853Authorization Bypass Through User-Controlled Key vulnerabili…2.3
• CVE-2026-81855A hardcoded cryptographic client authentication key vulnerab…9.1
• CVE-2026-81858IBM i 7.3, 7.4, 7.5, and 7.6 could allow a remote authentica…8.1
• CVE-2026-81859CP4BA - IBM Enterprise Records could allow a local attacker …6.2
• CVE-2026-8186A vulnerability was detected in Open5GS up to 2.7.7. This af…7.5
• CVE-2026-81861CWE-522: Insufficiently Protected Credentials vulnerability …5.9
• CVE-2026-81862Apache Airflow's Teradata provider embedded cloud storage cr…6.5
• CVE-2026-81866Apache NiFi 2.9.0 through 2.11.0 provide Connector configura…4.3