Bandit: Unauthenticated DoS via chunked request trailers in Bandit HTTP/1 decoder — CVE-2026-39806

Summary

### Summary A worker-pinning denial of service in Bandit's HTTP/1 chunked transfer decoder. Any unauthenticated client that sends a `Transfer-Encoding: chunked` request whose body ends with a trailer field (RFC 9112 §7.1.2 explicitly permits this) causes the connection's worker process to spin forever in an infinite recursion. A handful of concurrent connections are sufficient to exhaust the listener pool and…

Product

erlang: bandit

What to do

General, cautious steps (verify details in the official source):

• Prioritize patching or mitigation immediately (treat as actively risky).
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Related advisories