CVE-2026-39806
Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in mtrudel bandit allows unauthenticated remote denial of service via worker process exhaustion.
Published May 13, 2026 · corrected/updated Jun 17, 2026 · mtrudel bandit · evidence confidence medium
Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in mtrudel bandit allows unauthenticated remote denial of service via worker process exhaustion. 'Elixir.Bandit.HTTP1.Socket':do_read_chunked_data!/5 in lib/bandit/http1/socket.ex terminates only when the last-chunk line 0\r\n is followed immediately by the empty trailer line \r\n. RFC 9112 §7.1.2 permits zero or more trailer fields between them. When trailers are present, none of the match clauses fit: the catch-all arm computes a negative to_read, calls read_available!/2, receives > on timeout, and tail-recurses with unchanged state. The worker process is pinned for the lifetime of the TCP connection. A handful of concurrent connections sending RFC-conformant chunked requests with trailer fields is sufficient to exhaust the Bandit worker pool and render the server unresponsive to all further traffic. No authentication, special headers, or large payload is required. Proxies such as NGINX and HAProxy legitimately forward trailer-bearing requests, so servers behind such proxies may be affected without any malicious client involvement. This issue affects bandit: from 1.6.1 before 1.11.1.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-39806 is a high public vulnerability record for mtrudel bandit. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether mtrudel bandit is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: mtrudel/bandit. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 8.7. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-835. Sources contributing to this record: cve_org, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Technology hubs
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
May 13, 2026 · NIST NVD
Detected
Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in mtrudel bandit allows unauthenticated remote denial of service via worker process exhaustion. 'Elixir.Bandit.HTTP1.Socket':do_read_chunked_data!/5 in lib/bandit/http1/socket.ex terminates only when the last-chunk line 0\r\n is followed immediately by the empty trailer line \r\n. RFC 9112 §7.1.2 permits zero or more trailer fie
Jun 17, 2026 · NIST NVD
Updated
Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in mtrudel bandit allows unauthenticated remote denial of service via worker process exhaustion. 'Elixir.Bandit.HTTP1.Socket':do_read_chunked_data!/5 in lib/bandit/http1/socket.ex terminates only when the last-chunk line 0\r\n is followed immediately by the empty trailer line \r\n. RFC 9112 §7.1.2 permits zero or more trailer fie
Affected
- cpe mtrudel/banditversion unspecified
Sources
- CVE.orgVulnerability recordCVE-2026-39806
Official CVE identifier
cve.org - NIST NVDVulnerability recordCVE-2026-39806
Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in mtrudel bandit allows unauthenticated remote denial of service via worker process exhaustion. 'Elixir.Bandit.HTTP1.Socket':do_read_chunked_data!/5 in lib/bandit/http1/socket.ex terminates only when the last-
nvd.nist.gov