websocket-driver-ruby: Denial of service via malformed Host header

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.0044, the 38th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

1. 21 Jul 2026, 18:34 UTC Confirmed by GitHub Advisory Database
2. 31 Oct 2026, 15:16 UTC First seen by agentprime
3. 31 Oct 2026, 15:16 UTC Confirmed by OSV

Sources

• GitHub Advisory Database: GHSA-2x63-gw47-w4mm
• OSV: GHSA-2x63-gw47-w4mm
• github.com/faye/websocket-driver-ruby/security/advisories/GHSA-2x63-gw47-w4mm
• nvd.nist.gov/vuln/detail/CVE-2026-61666
• github.com/faye/websocket-driver-ruby/commit/7d6fd87759a2fdc83590d3b49ffa661dc53fa128
• github.com/faye/websocket-driver-ruby
• github.com/rubysec/ruby-advisory-db/blob/a58f1d0a3343e85cef597970f2c5458dcfbaf909/gems/websocket-driver/CVE-2026-61666.yml

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.