---
id: "CVE-2026-125406"
page: "https://infrastack.ai/live/CVE-2026-125406"
kind: "vulnerability"
aliases: ["CVE-2026-125406"]
title: "Ettercap: telnet dissector backspace handling corrupts stack, may run code as root"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["ettercap", "linux", "network-sniffing", "other"]
not_affected_if: ["ettercap-not-installed"]
published_at: "2026-11-10T00:17:15+00:00"
first_seen_at: "2026-11-10T00:28:45+00:00"
updated_at: "2026-11-10T00:29:46+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125406", "first_seen_at": "2026-11-10T00:28:45+00:00"}]
exploit_sources: []
---

# Ettercap: telnet dissector backspace handling corrupts stack, may run code as root

Link for people: https://infrastack.ai/live/CVE-2026-125406 (this .md is for agents)

Ettercap's telnet dissector decrements its output pointer on backspace without a lower bound check, so a crafted telnet stream with more backspaces than preceding characters writes below a stack buffer. An attacker can corrupt the stack of the Ettercap process, which normally runs as root.

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

## How to check

- Ettercap is in the affected range if its version is `0.8.4.1` or earlier (through `0.8.4.1`)
- Look at the Ettercap install on hosts that sniff network traffic; the flaw is in src/dissectors/ec_telnet.c

## Fix

- Ettercap versions after `0.8.4.1` are not stated as fixed in the sources; check the linked patch and vendor advisory for the fixed version

## Timeline

- 2026-11-10T00:28:45+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125406

## Documents

- [advisory] Vendor advisory: github.com https://github.com/Ettercap/ettercap/security/advisories/GHSA-w5ch-7c4x-crcc
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ettercap-through-0.8.4.1-stack-buffer-underwrite-via-telnet-dissector-backspace-handling
- [fix] Patch: github.com https://github.com/Ettercap/ettercap/commit/1d8badb713579419a29a494bb463a1af59707e98

## From the sources

Ettercap through 0.8.4.1 contains a stack buffer underwrite vulnerability in the telnet dissector in src/dissectors/ec_telnet.c that decrements the output pointer on backspace without a lower bound check. Attackers can send a telnet stream with more backspaces than preceding characters to write below the stack buffer, corrupting the stack of the Ettercap process that normally runs as root.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_