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8.7
CVE-2026-125406: Ettercap may let attackers corrupt its memory via telnet
CVE-2026-125406 · published 4 days ago
Summary
The network analysis tool Ettercap (versions up to 0.8.4.1) can be tricked by specially crafted Telnet data that includes many backspace characters. This causes the program to write outside its intended memory area, potentially allowing an attacker to alter the program while it runs with high privileges. Update to a newer version of Ettercap or apply the vendor's patch to stop the problem.
What to do
The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| – | ettercap | ettercap | <= 0.8.4.1 |
| Ubuntu:16.04:LTS | canonical | ettercap | All versions |
Original advisory text
Ettercap through 0.8.4.1 Stack Buffer Underwrite via Telnet Dissector Backspace Handling
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.
References
- https://github.com/Ettercap/ettercap/security/advisories/GHSA-w5ch-7c4x-crcc vendor-advisory
- https://github.com/Ettercap/ettercap/commit/1d8badb713579419a29a494bb463a1af5970... patch
- https://github.com/Ettercap/ettercap/pull/1330 issue-tracking patch
- https://github.com/Ettercap/ettercap/blob/v0.8.4.1/src/dissectors/ec_telnet.c#L1... technical-description
- https://www.vulncheck.com/advisories/ettercap-through-0.8.4.1-stack-buffer-under... third-party-advisory
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/125xxx/CVE-2026-1254... Vendor Advisory
- https://github.com/Ettercap/ettercap Product
- https://nvd.nist.gov/vuln/detail/CVE-2026-125406 Vendor Advisory
- https://ubuntu.com/security/CVE-2026-125406 Third Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2026-125406 Third Party Advisory
Internet-facing
14 days
Internal
At next upgrade
- Not known to be exploited
- Needs hands-on effort to exploit (estimated)
- Gives an attacker full control (estimated)
Severity
8.7
High
Type
CWE-124Buffer Underwrite ('Buffer Underflow')
Timeline
Published9 Nov 2026
Updated13 Nov 2026
First seen10 Nov 2026
Sources
CVE-2026-125406 · NVD
CVE-2026-125406 · MITRE
CVE-2026-125406 · OSV
GHSA-w5ch-7c4x-crcc · GHSA
UBUNTU-CVE-2026-125406 · OSV
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