{"schemaVersion":3,"id":"CVE-2026-32688","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"Allocation of Resources Without Limits or Throttling vulnerability in elixir-plug plug_cowboy allows unauthenticated remote denial of service via atom table exhaustion.\n\nPlug.Cowboy.Conn.conn/1 in lib/plug/cowboy/conn.ex calls String.to_atom/1 on the value returned by :cowboy_req.scheme/1. For HTTP/2 connections, cowlib passes the client-supplied :scheme pseudo-header value through verbatim without validation. Each unique value permanently allocates a new entry in the BEAM atom table. Since atoms are never garbage-collected and the atom table has a fixed limit (default 1,048,576), an unauthenticated attacker can exhaust the table by sending HTTP/2 requests with unique :scheme values, causing the Erlang VM to abort with system_limit and taking down the entire node.\n\nThis vulnerability does not affect HTTP/1.1, where cowboy derives the scheme from the listener type rather than from a client-supplied header.\n\nThis issue affects plug_cowboy: from 2.0.0 before 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of Resources Without Limits or Throttling","description":"The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.","type":"weakness","status":"Incomplete","abstraction":"Base","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/770.html"}],"affected":[{"vendor":"elixir-plug","product":"plug_cowboy","name":"plug_cowboy","label":"plug_cowboy","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 2.0.0, < 2.8.1","noFixRecorded":false,"fixedIn":null},{"text":"≥ 12ecfd024bb179d48b018fecf074e43fe6a19c83, < bfb34cb45eb354e56437f7023fb306de1bf9c19b","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 2.0.0, < 2.8.1 | ≥ 12ecfd024bb179d48b018fecf074e43fe6a19c83, < 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Advisory"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-32688","label":"osv.dev/vulnerability/EEF-CVE-2026-32688","hostname":"osv.dev","tags":["Related","Third Party Advisory"]},{"url":"https://github.com/elixir-plug/plug_cowboy/commit/bfb34cb45eb354e56437f7023fb306de1bf9c19b","label":"github.com/elixir-plug/plug_cowboy/commit/bfb34cb45eb354e56437f7023fb306de1bf9c19b","hostname":"github.com","tags":["Patch"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-04-27T13:45:35.160Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-04-29T17:08:07.227Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":35,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-19T21:01:49.197Z","stale":false,"partial":false}}