Is CVE-2026-125406 being exploited in the wild?

At the time of the last update, CVE-2026-125406 was not in the CISA Known Exploited Vulnerabilities catalog. Recheck the catalog regularly.

How do I fix CVE-2026-125406?

Upgrade Ettercap to the fixed version named in the vendor advisory listed under Technical References. If you cannot patch right away, limit network access to the affected component and monitor it closely until you can.

How serious is CVE-2026-125406?

It is rated high with a CVSS base score of 8.7. The flaw needs local or adjacent access, needs no login, and needs no user interaction. In CTEM terms, combine that with how exposed and important the affected system is to set the real priority.

CVE-2026-125406: Ettercap Security Vulnerability

CVSS

8.7 HIGH

EPSS

n/a

CISA KEV

Not listed

CWE

CWE-124

Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS

CVE-2026-125406 Overview

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.

Critical Impact

Local or adjacent, unauthenticated attackers can exploit this Security Vulnerability in Ettercap. The CVSS base score is 8.7 (High).

Affected Products

Ettercap: see the vendor advisory for the exact affected versions

Discovery Timeline

2026-11-10: CVE-2026-125406 published to the National Vulnerability Database by disclosure@vulncheck.com
2026-11-10: last updated in the NVD database

Technical Details for CVE-2026-125406

Vulnerability Analysis

CVE-2026-125406 is a Security Vulnerability weakness (CWE-124) in Ettercap. Based on its CVSS vector, the flaw needs local or adjacent access, needs no login, and needs no user interaction.

With a CVSS base score of 8.7, apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Root Cause

The vendor description states: 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.

Attack Vector

Based on the CVSS vector, the flaw needs local or adjacent access, needs no login, and needs no user interaction. Attack complexity is low complexity.

No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Detection Methods for CVE-2026-125406

Detection Strategies

Inventory every instance of Ettercap and compare the running version with the affected range above.
Check external attack surface scans for internet facing instances of the component.
Run an authenticated vulnerability scan once your scanner ships a check for this CVE.

Monitoring Recommendations

Forward Ettercap application, access and audit logs to your SIEM for retrospective hunting.
Alert on new processes, configuration changes or outbound connections from the affected service.
Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.

How to Mitigate CVE-2026-125406

Immediate Actions Required

Apply the fixed version of Ettercap named in the vendor advisory.
Prioritize internet facing and business critical instances first.
Rescan after the change to confirm the exposure is closed.

Patch Information

Use the fixed version listed in the vendor advisory for Ettercap.

Workarounds

If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.

CWE References

CWE-124 More CVEs with this weakness

Technical References

This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.

Frequently asked questions

CVE-2026-125406 is a high severity Security Vulnerability in Ettercap with a CVSS score of 8.7. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Related CVEs

HIGH8.2

CVE-2026-0966

Libssh

A flaw was found in libssh. The API function `ssh_get_hexa()` is vulnerable to a denial of service when processing zero-length input. This can be exploited remotely by an attacker during GSSAPI (Generic Security Service Application Program Interface) authentication if the server's logging verbosity is set to `SSH_LOG_PACKET (3)` or higher. Successful exploitation could lead to a self-Denial of Service of the per-connection daemon process.

Mar 26, 2026

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