---
id: "CVE-2026-24061"
kind: "vulnerability"
aliases: ["CVE-2026-24061"]
title: "telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a \"-f root\" value for the USER\u2026"
severity: "critical"
cvss: 9.8
epss: null
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "GNU InetUtils", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "gnu inetutils", "fixed": [], "affected": ">= 1.9.3, <= 2.7", "ecosystem": "vendor"}, {"name": "debian linux", "fixed": [], "affected": "= 11.0", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "gnu-inetutils", "infrastructure", "linux", "self-hosted", "telnetd"]
not_affected_if: ["ssh-only-access", "telnetd-not-running"]
published_at: "2026-01-21T07:16:01+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T23:44:51+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-24061", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-24061", "first_seen_at": "2026-10-23T23:44:51+00:00"}]
---

# telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a "-f root" value for the USER…

GNU InetUtils telnetd passes a USER environment variable value of "-f root" as an argument, which skips the login password check. A remote attacker can log in as root without credentials.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:GNU InetUtils affected ? fixed ?
- vendor:gnu inetutils affected >= 1.9.3, <= 2.7 fixed ?
- vendor:debian linux affected = 11.0 fixed ?

## How to check

Check whether telnetd from GNU InetUtils is running: ss -tlnp | grep :23

## Fix

Apply vendor mitigations per CISA guidance, or disable telnetd and use SSH instead.

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-24061
- 2026-10-23T23:44:51+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-24061

## From the sources

GNU InetUtils contains an argument injection vulnerability in telnetd that could allow for remote authentication bypass via a "-f root" value for the USER environment variable.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_