{"id":"CVE-2026-97200","kind":"vulnerability","aliases":["CVE-2026-97200"],"related":[],"title":"hackney: malicious server can exhaust client memory with large responses","description":"Allocation of Resources Without Limits or Throttling vulnerability in hackney_conn in benoitc hackney allows a malicious HTTP server to exhaust client memory via an oversized or highly compressed response body. hackney:request/5 and hackney:body/1 return the whole response body, and nothing bounds how much the connection process buffers. Any server the client requests can trigger it.\n\nhackney_conn:read_full_body/2 and the HTTP/2 and HTTP/3 accumulators append every chunk until the body ends. With {auto_decompress, true} the buffered body is then inflated in one step with zlib:gunzip/1 or zlib:inflate/2, which return the whole output at once.\n\nThis issue affects hackney: from 2.0.0-beta.1 before 4.9.0.","summary":"The Erlang HTTP client hackney buffers entire response bodies without any size limit, and decompresses them in one step. A malicious HTTP server the client calls can send an oversized or highly compressed body and exhaust the client's memory.","severity":"high","cvss":8.2,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["elixir","erlang","hackney","package"],"not_affected_if":["hackney-4.9.0-or-later","hackney-not-used","trusted-servers-only"],"how_to_check":"- Check the hackney version in `rebar.lock` or `mix.lock` (or the lock file for your build tool) and see whether it falls in `2.0.0-beta.1` to before `4.9.0`.\n- Look for calls to `hackney:request/5` or `hackney:body/1` that fetch from servers you do not control.","fix":"- Upgrade hackney to `4.9.0` or later.","status":"open","published_at":"2026-10-26T14:16:42+00:00","first_seen_at":"2026-10-26T14:30:37+00:00","triaged_at":"2026-10-26T14:32:17+00:00","updated_at":"2026-10-26T14:32:17+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-26T14:32:17Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade hackney to `4.9.0` or later.","reach":"internet","title":"hackney: malicious server can exhaust client memory with large responses","impact":"medium","summary":"The Erlang HTTP client hackney buffers entire response bodies without any size limit, and decompresses them in one step. A malicious HTTP server the client calls can send an oversized or highly compressed body and exhaust the client's memory.","category":"package","nicknames":[],"who_cares":["erlang","elixir","hackney"],"confidence":0.7,"needs_auth":"no","worst_case":"Remote server crashes the client process by exhausting its memory.","analyst_note":"","how_to_check":"- Check the hackney version in `rebar.lock` or `mix.lock` (or the lock file for your build tool) and see whether it falls in `2.0.0-beta.1` to before `4.9.0`.\n- Look for calls to `hackney:request/5` or `hackney:body/1` that fetch from servers you do not control.","needs_analyst":false,"not_affected_if":["hackney-not-used","trusted-servers-only","hackney-4.9.0-or-later"],"who_is_affected":"Erlang or Elixir services that use hackney as an HTTP client and fetch data from servers they do not fully trust, such as third-party APIs, webhooks or user-supplied URLs. Services that only call fixed internal endpoints under your control are at much lower risk. Teams not using hackney can skip it.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000617,"input_tokens":3481,"output_tokens":538,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':12A,15A '-97200':13A,16A '2.0.0':168C '4.9.0':171C 'accumul':129C 'affect':165C 'alloc':61C 'allow':75C 'append':130C 'auto':138C 'benoitc':73C 'beta.1':169C 'bodi':29B,54B,91C,101C,135C,143C 'body/1':96C 'body/2':123C 'bound':104C 'buffer':26B,110C,142C 'call':46B 'chunk':132C 'client':6A,24B,45B,58B,82C,114C 'compress':53B,89C 'conn':71C,120C 'connect':108C 'cve':11A,14A 'decompress':35B,139C 'elixir':17B 'end':136C 'entir':27B 'erlang':18B,22B 'everi':131C 'exhaust':5A,56B,81C 'full':122C 'gunzip/1':152C 'hackney':1A,19B,25B,70C,74C,92C,95C,119C,166C 'high':52B,88C 'http':23B,42B,78C 'http/2':126C 'http/3':128C 'inflat':146C 'inflate/2':155C 'issu':164C 'larg':9A 'limit':33B,65C 'malici':2A,41B,77C 'memori':7A,60B,83C 'much':106C 'noth':103C 'one':38B,148C 'output':160C 'overs':50B,86C 'packag':20B 'process':109C 'read':121C 'request':115C 'request/5':93C 'resourc':63C 'respons':10A,28B,90C,100C 'return':97C,157C 'send':48B 'server':3A,43B,79C,112C 'size':32B 'step':39B,149C 'throttl':67C 'trigger':117C 'true':140C 'via':84C 'vulner':68C 'whole':99C,159C 'without':30B,64C 'zlib':151C,154C","nicknames":[],"mitigations":[],"who_affected":"Erlang or Elixir services that use hackney as an HTTP client and fetch data from servers they do not fully trust, such as third-party APIs, webhooks or user-supplied URLs. Services that only call fixed internal endpoints under your control are at much lower risk. Teams not using hackney can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-26T14:16:42+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/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-2026-97200","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97200","severity":null,"published_at":"2026-10-26T14:16:42+00:00","modified_at":"2026-10-26T14:16:42+00:00","first_seen_at":"2026-10-26T14:30:37+00:00","fetched_at":"2026-10-26T14:30:37+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"}