{"id":"CVE-2026-56814","summary":"Plug: multipart :length limit is not charged for part headers, enabling unbounded temp-file creation (denial of service)","details":"Plug.Parsers.MULTIPART, the multipart request-body parser used to handle file uploads and multipart forms, does not enforce its :length budget against all consumed resources, allowing an unauthenticated remote attacker to cause denial of service. The parser charges the :length limit only for part body bytes; part header bytes are never counted, and a part with an empty body costs zero.\n\nBecause every part whose Content-Disposition carries a non-empty filename creates a fresh temporary file (via Plug.Upload) and retains a Plug.Upload struct for the duration of the request, an attacker can send a single request composed of many empty-body file parts. Such a request stays well under the configured :length limit (8,000,000 bytes by default) while creating one temporary file per part, leading to inode and disk exhaustion and unbounded memory growth. Any application using Plug.Parsers with the :multipart parser is affected, and no authentication is required, only reachability of a multipart endpoint over HTTP.\n\nThis vulnerability is associated with program files lib/plug/parsers/multipart.ex and program routines Plug.Parsers.MULTIPART.parse_multipart/2, Plug.Parsers.MULTIPART.parse_multipart_headers/5, Plug.Parsers.MULTIPART.parse_multipart_body/4, and Plug.Parsers.MULTIPART.parse_multipart_file/4.\n\nThis issue affects plug: from 1.4.0 before 1.16.6, from 1.17.0 before 1.17.4, from 1.18.0 before 1.18.5, from 1.19.0 before 1.19.5, and from 1.20.0 before 1.20.3.","aliases":["EEF-CVE-2026-56814","GHSA-95qv-c9g9-rm63"],"modified":"2026-07-15T01:49:02.777262537Z","published":"2026-07-10T11:14:35.574Z","database_specific":{"cna_assigner":"EEF","cwe_ids":["CWE-770"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56814.json","unresolved_ranges":[{"extracted_events":[{"introduced":"1.4.0"},{"fixed":"1.16.6"},{"introduced":"1.17.0"},{"fixed":"1.17.4"},{"introduced":"1.18.0"},{"fixed":"1.18.5"},{"introduced":"1.19.0"},{"fixed":"1.19.5"},{"introduced":"1.20.0"},{"fixed":"1.20.3"},{"introduced":"c52b2f32c90bccd718202bafccb5f95594e30183"},{"fixed":"*"}],"source":"AFFECTED_FIELD"},{"extracted_events":[{"introduced":"1.4.0"},{"fixed":"1.16.6"},{"introduced":"1.17.0"},{"fixed":"1.17.4"},{"introduced":"1.18.0"},{"fixed":"1.18.5"},{"introduced":"1.19.0"},{"fixed":"1.19.5"},{"introduced":"1.20.0"},{"fixed":"1.20.3"}],"source":"CPE_FIELD"},{"source":"DESCRIPTION","extracted_events":[{"introduced":"1.4.0"},{"fixed":"1.16.6"},{"introduced":"1.17.0"},{"fixed":"1.17.4"},{"introduced":"1.18.0"},{"fixed":"1.18.5"},{"introduced":"1.19.0"},{"fixed":"1.19.5"},{"introduced":"1.20.0"},{"fixed":"1.20.3"}]}]},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-56814.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-56814"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56814.json"},{"type":"ADVISORY","url":"https://github.com/elixir-plug/plug/security/advisories/GHSA-95qv-c9g9-rm63"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56814"},{"type":"FIX","url":"https://github.com/elixir-plug/plug/commit/0ee8afcc61466dc5f7a8f048d0632c899165b81f"},{"type":"FIX","url":"https://github.com/elixir-plug/plug/commit/56edca2ce35fe5589cd581644d8a4493fa5f484e"},{"type":"FIX","url":"https://github.com/elixir-plug/plug/commit/981597d3a4271ede64373c7a731702a42c500dd6"},{"type":"FIX","url":"https://github.com/elixir-plug/plug/commit/cae36053350e5215a4e0ca33cd130af9c5fc6364"},{"type":"FIX","url":"https://github.com/elixir-plug/plug/commit/df97d3f17f808a9916a7700a701fb85314559d56"},{"type":"FIX","url":"https://github.com/elixir-plug/plug/commit/f7effaed811c00b5f5bf817936bfd9c5df27b7dc"},{"type":"PACKAGE","url":"https://github.com/elixir-plug/plug"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/elixir-plug/plug","events":[{"introduced":"0"},{"fixed":"0ee8afcc61466dc5f7a8f048d0632c899165b81f"},{"fixed":"56edca2ce35fe5589cd581644d8a4493fa5f484e"},{"fixed":"981597d3a4271ede64373c7a731702a42c500dd6"},{"fixed":"cae36053350e5215a4e0ca33cd130af9c5fc6364"},{"fixed":"df97d3f17f808a9916a7700a701fb85314559d56"},{"fixed":"f7effaed811c00b5f5bf817936bfd9c5df27b7dc"}],"database_specific":{"source":"REFERENCES"}}],"versions":["v1.20.1","v1.20.0","v1.15.3","v1.17.0","v1.18.1","v1.19.1","v1.18.0","v1.16.1","v1.16.0","v1.15.2","v1.15.1","v1.15.0","v1.14.2","v1.14.1","v1.14.0","v1.13.5","v1.13.4","v1.13.3","v1.13.2","v1.13.1","v1.13.0","v1.12.1","v1.12.0","v1.11.1","v1.11.0","v1.10.3","v1.10.2","v1.10.1","v1.10.0","v1.9.0","v1.8.2","v1.8.1","v1.8.0","v1.7.2","v1.7.1","v1.7.0","v1.6.1","v1.6.0","v1.5.1","v1.5.0","v1.5.0-rc.2","v1.5.0-rc.1","v1.4.3","v1.5.0-rc.0","v1.4.2","v1.4.1","v1.4.0","v1.4.0-rc.0","v1.3.2","v1.2.2","v1.3.1","v1.3.0","v1.2.1","v1.2.0","v1.2.0-rc.0","v1.1.4","v1.1.3","v1.1.2","v1.1.1","v1.1.0","v1.0.2","v1.0.1","v1.0.0","v0.14.0","v0.13.1","v0.13.0","v0.12.2","v0.12.0","v0.11.3","v0.11.2","v0.11.1","v0.11.0","v0.10.0","v0.9.0","v0.8.4","v0.8.3","v0.8.2","v0.8.1","v0.8.0","v0.7.0","v0.6.0","v0.5.3","v0.5.2","v0.5.1","v0.5.0","v0.4.4","v0.4.3","v0.4.2","v0.4.1","v0.4.0","v0.3.0","v0.2.0","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-56814.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"}]}