{"@context":"https://openvex.dev/ns/v0.2.0","@id":"https://database.harborguard.co/cve/CVE-2026-43974/vex.json","author":"HarborGuard Database","role":"Document Creator","timestamp":"2026-06-08T16:34:38.989Z","version":1,"tooling":"HarborGuard Database (https://database.harborguard.co)","statements":[{"vulnerability":{"name":"CVE-2026-43974","@id":"https://www.cve.org/CVERecord?id=CVE-2026-43974","description":"Unexpected Status Code or Return Value vulnerability in ninenines gun (gun_http module) allows a malicious HTTP server to force the client into raw protocol mode via an unsolicited 101 Switching Protocols response.\n\nIn gun_http:handle_inform/8, when a 101 Switching Protocols response is received over HTTP/1.1, the function verifies only that the Upgrade header is syntactically valid and that the stream reference is a plain reference(). It does not check whether the client ever sent an Upgrade or"},"products":[{"@id":"cpe:2.3:a:ninenines:gun:*:*:*:*:*:*:*:*","identifiers":{"cpe23":"cpe:2.3:a:ninenines:gun:*:*:*:*:*:*:*:*"}}],"status":"affected","action_statement":"Update to a fixed version: 2.4.0, 5b48068c29ce5e112cb149b5857c7d4dc319a81b.","timestamp":"2026-06-08T16:34:38.989Z"}]}