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.
https://github.com/Ettercap/ettercap/security/advisories/GHSA-w5ch-7c4x-crcc
https://github.com/Ettercap/ettercap/pull/1330
https://github.com/Ettercap/ettercap/commit/1d8badb713579419a29a494bb463a1af59707e98
https://github.com/Ettercap/ettercap/blob/v0.8.4.1/src/dissectors/ec_telnet.c#L150-L159
Published: 2026-11-10
Updated: 2026-11-10
Base Score: 8.3
Vector: CVSS2#AV:A/AC:L/Au:N/C:C/I:C/A:C
Severity: High
Base Score: 8.8
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: High
Base Score: 8.7
Vector: 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
Severity: High
EPSS: 0.0024