{"id":"DEBIAN-CVE-2026-8466","details":"Allocation of Resources Without Limits or Throttling vulnerability in ninenines cowboy allows denial of service via unbounded buffer accumulation in multipart header parsing.  cowboy_req:read_part/3 in src/cowboy_req.erl accumulates incoming request bytes into a Buffer binary with no upper-bound check. When cow_multipart:parse_headers/2 returns more or {more, Buffer2}, the function reads up to Length bytes (default 64 KB) from the request body and recurses with the enlarged buffer. There is no equivalent of the byte_size(Acc) \u003e Length guard present in the sibling function read_part_body/4. An unauthenticated attacker can send a multipart/form-data request whose body never yields a complete header section — for example, a body that never contains the advertised boundary delimiter, or one whose header lines never contain \\r\\n\\r\\n — and force the server process to accumulate memory linearly with the bytes the protocol layer is willing to deliver. A handful of concurrent such uploads is sufficient to exhaust BEAM memory.  This issue affects cowboy from 2.0.0 before 2.15.0.","modified":"2026-09-14T17:03:37.170649194Z","published":"2026-05-13T19:17:30.540Z","upstream":["CVE-2026-8466"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-8466"}],"affected":[{"package":{"name":"erlang-cowboy","ecosystem":"Debian:14","purl":"pkg:deb/debian/erlang-cowboy?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.16.1+dfsg-1"}]}],"versions":["0.10.0+dfsg1-1","0.6.1-1","0.6.1-2","0.6.1-3","0.6.1-4","0.8.6+dfsg-1","0.8.6+dfsg1-1","1.0.0+dfsg1-1","2.0.0~pre.1+dfsg1-1","2.0.0~pre.1+dfsg1-2","2.0.0~pre.1+dfsg1-3","2.0.0~pre.1+dfsg1-4"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-8466.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}