Ettercap through 0.8.4.1 Stack Buffer Underwrite via Telnet Dissector Backspace Handling
Affects Ettercap 0.8.4.1 and earlier when it dissects telnet sessions on TCP 23. The checked facts list no vendor rating and no fixed release.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fix or patch referenced
- Who is exposed
- Not reported
Do first: Apply the patch listed under Evidence.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 9/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.7/10CVSS 8.7
- No patch0/5No signal
What would change the score
- Would score about 64 if added to CISA KEV
- Would score about 59 if CISA's SSVC rates exploitation active
- Would score about 31 if advisories confirm default setups are exposed
What to do
Apply the patch listed under Evidence.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- Ettercap ettercap
through 0.8.4.1
Evidence 5
- Advisory
- Patch
- Patch
- Repository
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-125406
Is CVE-2026-125406 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
Attacker-chosen bytes can be written below a stack buffer through the telnet dissector's backspace handling. This corrupts the stack of the Ettercap process, which normally runs as root.Source: vulncheck.com, github.com
Which versions are affected by CVE-2026-125406?
ettercap: through 0.8.4.1.Source: cve.now feed data
Am I affected, and how do I check?
Ettercap versions up to and including 0.8.4.1 are affected, but only when it dissects a telnet session on TCP 23 that reaches the telnet dissector. Check the installed Ettercap version and whether telnet traffic is being dissected.Source: vulncheck.com, github.com
How do I fix CVE-2026-125406?
The checked facts name no fixed version and no workaround, so no upgrade target can be given from them. Check the Ettercap project or the advisory for a fix before relying on any version.Source: vulncheck.com, github.com