Terminal escape sequence injection in Hex via unneutralized server-supplied output
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.
CVE-2026-81856
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-81856
hex
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
hex
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"cpes": [
"cpe:2.3:a:hexpm:hex:*:*:*:*:*:*:*:*"
],
"repo": "https://github.com/hexpm/hex",
"vendor": "hexpm",
"modules": [
"'Elixir.Mix.Tasks.Hex.Search'"
],
"product": "hex",
"versions": [
{
"status": "affected",
"version": "0.0.1",
"lessThan": "2.5.2",
"versionType": "semver"
}
],
"packageURL": "pkg:otp/hex?repository_url=https:%2F%2Fgithub.com%2Fhexpm%2Fhex&vcs_url=repository_url=git%2Bhttps:%2F%2Fgithub.com%2Fhexpm%2Fhex.git",
"packageName": "hex",
"programFiles": [
"lib/mix/tasks/hex.search.ex"
],
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "'Elixir.Mix.Tasks.Hex.Search':run/1"
}
]
},
{
"cpes": [
"cpe:2.3:a:hexpm:hex:*:*:*:*:*:*:*:*"
],
"repo": "https://github.com/hexpm/hex",
"vendor": "hexpm",
"modules": [
"'Elixir.Mix.Tasks.Hex.Search'"
],
"product": "hex",
"versions": [
{
"status": "affected",
"version": "211303e3f68f5d3ce06450c1ff1a7a770a9ab236",
"lessThan": "dd3305ddf0032f6d0b468fd40dbbc3072bfcb8b8",
"versionType": "git"
}
],
"packageURL": "pkg:github/hexpm/hex",
"packageName": "hexpm/hex",
"programFiles": [
"lib/mix/tasks/hex.search.ex"
],
"collectionURL": "https://github.com",
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "'Elixir.Mix.Tasks.Hex.Search':run/1"
}
]
}
]- Related CVEs
- CVE-2026-81856
Source reference:
/cveMetadata/cveId
Publisher severity
low
Source reference: /containers/cna/metrics
- Event
- #32884 · Revision 1
- Added to Heist Feed
- Publisher date