Ettercap through 0.8.4.1 Use-After-Free via PCRE2 Filter Substitution
Affects Ettercap through 0.8.4.1 when a filter uses a pcre_regex() substitution outside unoffensive mode and the build includes PCRE2 support.
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 use-after-free vulnerability in func_pcre() in src/ec_filter.c that reads the PCRE2 ovector after freeing match data. Network-adjacent attackers can send packets matching a loaded pcre_regex() substitution filter to corrupt memory and potentially execute code 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-2026-125400
Is CVE-2026-125400 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?
A use-after-free bug in Ettercap's PCRE2 filter substitution corrupts heap memory using attacker-influenced sizes and offsets. Ettercap normally runs as root, so the corruption could potentially lead to code execution as root.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-125400?
ettercap: through 0.8.4.1.Source: cve.now feed data
Am I affected, and how do I check?
Ettercap through 0.8.4.1 is affected only when a filter contains a pcre_regex() substitution (a pcre_regex op with a replacement string), Ettercap is not in unoffensive mode, and it is built with PCRE2 support. To check a setup, review the filter files for pcre_regex operations with replacement strings, confirm whether unoffensive mode is in use, and check the build for PCRE2 support.Source: github.com, vulncheck.com
How do I fix CVE-2026-125400?
The checked facts do not name a fixed Ettercap release, so no specific upgrade target is confirmed. Check the project's advisory for a fixed version, and until then avoid running filters that contain pcre_regex() substitutions outside unoffensive mode.Source: github.com, vulncheck.com