CVE-2026-125406 (CVSS 8.8)

Description

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.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.15%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-124 CWE-124

References

Other References

https://github.com/Ettercap/ettercap/blob/v0.8.4.1/src/dissectors/ec_telnet.c#L150-L159 https://github.com/Ettercap/ettercap/commit/1d8badb713579419a29a494bb463a1af59707e98 https://github.com/Ettercap/ettercap/pull/1330 https://github.com/Ettercap/ettercap/security/advisories/GHSA-w5ch-7c4x-crcc https://www.vulncheck.com/advisories/ettercap-through-0.8.4.1-stack-buffer-underwrite-via-telnet-dissector-backspace-handling

Frequently Asked Questions

What is CVE-2026-125406? +

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. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-125406? +

CVE-2026-125406 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-125406? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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