Quick answers
- Is CVE-2026-125403 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-125403 being exploited in the wild.
- How severe is CVE-2026-125403?
- High severity, with a CVSS score of 8.1, published 10 November 2026.
- Which products and versions are affected?
- Ettercap through 0.8.4.1.
- Is there a fix for CVE-2026-125403?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-125403 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-125403?
- Check whether you run Ettercap at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is an out-of-bounds read and size_t underflow in the sslw_remove_sts() function in src/ec_sslwrap.c, triggered when stripping Strict-Transport-Security headers from intercepted HTTPS responses. The flaw results from a stale length value and an unchecked memmem() result that fails to validate the header's presence before attempting to remove it, allowing memory corruption when processing a malicious server response.
Affected products
- Ettercap Ettercap through 0.8.4.1
Timeline
- 2026-11-10: disclosed