{"id":"CVE-2026-115269","kind":"vulnerability","aliases":["CVE-2026-115269"],"related":[],"title":"Bandit: HTTP/2 frames let a client hold request streams open indefinitely","description":"Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/2 request body reader of mtrudel bandit allows an unauthenticated remote attacker to hold stream processes open indefinitely via WINDOW_UPDATE or empty SETTINGS frames sent while a Plug reads the request body.\n\nBandit.HTTP2.Stream.do_read_data/4 in lib/bandit/http2/stream.ex waits for each frame with a fresh read_timeout. A stream WINDOW_UPDATE, or the zero-delta window update that every empty SETTINGS frame delivers to all streams, ends the wait without delivering any body data, and the loop starts a new full countdown. A client that sends one of these 9-byte frames before each countdown expires keeps read_body blocked, together with the stream process and whatever the application holds while reading, for as long as it likes.\n\nThis issue affects bandit: from 1.4.0 before 1.14.0.","summary":"Bandit is an Elixir HTTP server. A remote client can send repeated WINDOW_UPDATE or empty SETTINGS frames while an application reads a request body, resetting the read timeout each time so the stream process stays blocked indefinitely.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["bandit","elixir","http2","package","phoenix","plug","self-hosted"],"not_affected_if":["bandit-below-1.4.0-or-1.14.0-plus","http1-only","http2-terminated-at-proxy"],"how_to_check":"- Check the Bandit version in `mix.lock` or `mix deps` output for `bandit`\n- Confirm whether the app serves HTTP/2 through Bandit (e.g., `:bandit` listener with HTTP/2 enabled)","fix":"- Upgrade `bandit` to `1.14.0` or later","status":"open","published_at":"2026-10-26T14:16:31+00:00","first_seen_at":"2026-10-26T14:30:36+00:00","triaged_at":"2026-10-26T14:32:07+00:00","updated_at":"2026-10-26T14:32:07+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-26T14:32:07Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade `bandit` to `1.14.0` or later","reach":"internet","title":"Bandit: HTTP/2 frames let a client hold request streams open indefinitely","impact":"medium","summary":"Bandit is an Elixir HTTP server. A remote client can send repeated WINDOW_UPDATE or empty SETTINGS frames while an application reads a request body, resetting the read timeout each time so the stream process stays blocked indefinitely.","category":"package","nicknames":[],"who_cares":["elixir","bandit","plug","phoenix","http2","self-hosted"],"confidence":0.7,"needs_auth":"no","worst_case":"Remote clients exhaust server stream processes and memory via indefinite blocking","analyst_note":"","how_to_check":"- Check the Bandit version in `mix.lock` or `mix deps` output for `bandit`\n- Confirm whether the app serves HTTP/2 through Bandit (e.g., `:bandit` listener with HTTP/2 enabled)","needs_analyst":false,"not_affected_if":["bandit-below-1.4.0-or-1.14.0-plus","http1-only","http2-terminated-at-proxy"],"who_is_affected":"Applications running Bandit from 1.4.0 before 1.14.0 that accept HTTP/2 connections and read request bodies through Plug. Exposure depends on whether the HTTP/2 listener is reachable from the internet or other untrusted clients. Deployments on HTTP/1.1 only, or behind a proxy that terminates HTTP/2 and speaks HTTP/1.1 to Bandit, are likely unaffected.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000656,"input_tokens":3541,"output_tokens":604,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-115269':14A,17A '-2026':13A,16A '1.14.0':201C '1.4.0':199C '9':165C 'affect':196C 'alloc':65C 'allow':82C 'applic':47B,184C 'attack':86C 'bandit':1A,18B,27B,81C,197C 'bandit.http2.stream.do':108C 'block':63B,175C 'bodi':51B,77C,107C,148C,174C 'byte':166C 'client':6A,35B,159C 'countdown':157C,170C 'cve':12A,15A 'data':149C 'data/4':110C 'deliv':138C,146C 'delta':130C 'elixir':19B,30B 'empti':42B,97C,135C 'end':142C 'everi':134C 'expir':171C 'frame':3A,44B,99C,116C,137C,167C 'fresh':119C 'full':156C 'hold':7A,88C,185C 'host':26B 'http':31B 'http/2':2A,75C 'http2':20B 'indefinit':11A,64B,92C 'issu':195C 'keep':172C 'let':4A 'lib/bandit/http2/stream.ex':112C 'like':193C 'limit':69C 'long':190C 'loop':152C 'mtrudel':80C 'new':155C 'one':162C 'open':10A,91C 'packag':21B 'phoenix':22B 'plug':23B,103C 'process':61B,90C,180C 'read':48B,54B,104C,109C,120C,173C,187C 'reader':78C 'remot':34B,85C 'repeat':38B 'request':8A,50B,76C,106C 'reset':52B 'resourc':67C 'self':25B 'self-host':24B 'send':37B,161C 'sent':100C 'server':32B 'set':43B,98C,136C 'start':153C 'stay':62B 'stream':9A,60B,89C,123C,141C,179C 'throttl':71C 'time':57B 'timeout':55B,121C 'togeth':176C 'unauthent':84C 'updat':40B,95C,125C,132C 'via':93C 'vulner':72C 'wait':113C,144C 'whatev':182C 'window':39B,94C,124C,131C 'without':68C,145C 'zero':129C 'zero-delta':128C","nicknames":[],"mitigations":[],"who_affected":"Applications running Bandit from 1.4.0 before 1.14.0 that accept HTTP/2 connections and read request bodies through Plug. Exposure depends on whether the HTTP/2 listener is reachable from the internet or other untrusted clients. Deployments on HTTP/1.1 only, or behind a proxy that terminates HTTP/2 and speaks HTTP/1.1 to Bandit, are likely unaffected.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-26T14:16:31+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-115269","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-115269","severity":null,"published_at":"2026-10-26T14:16:31+00:00","modified_at":"2026-10-26T14:16:31+00:00","first_seen_at":"2026-10-26T14:30:36+00:00","fetched_at":"2026-10-26T14:30:36+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}