{"id":"EEF-CVE-2026-82729","summary":"Quadratic chunk-size parsing in Mint.HTTP1.Parse allows CPU-exhaustion DoS","details":"## Summary\n\nInefficient Algorithmic Complexity vulnerability in elixir-mint mint allows a remote HTTP server to exhaust CPU on the client host and cause a denial of service.\n\n`parse_hex_prefix/2` in `lib/mint/http1/parse.ex` folds each hex digit of a chunked response's chunk-size field into an arbitrary-precision accumulator with `acc * 16 + digit` and imposes no limit on the digit count. Because the accumulator grows without bound, the multiplication is not constant time and one pass over `N` digits costs O(N squared). `handle_data/2` prepends `conn.buffer` and re-parses from the start on every socket message, so a server that dribbles the digits out in small packets makes the client pay that cost repeatedly. A run of roughly 512,000 hex digits costs over ten seconds of CPU in a single pass, measured on stock defaults. The parser reaches this state after a valid status line and a complete, valid header section, so an intermediary inspecting only headers sees an ordinary 200 response.\n\nThis issue affects mint: from 1.9.3 before 1.10.0.","aliases":["CVE-2026-82729","GHSA-7p8w-j234-7qc8"],"modified":"2026-09-08T02:45:03.377786799Z","published":"2026-09-04T14:31:20.562Z","database_specific":{"capec_ids":["CAPEC-130"],"cpe_ids":["cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"],"cwe_ids":["CWE-407"]},"references":[{"type":"ADVISORY","url":"https://github.com/elixir-mint/mint/security/advisories/GHSA-7p8w-j234-7qc8"},{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-82729.html"},{"type":"FIX","url":"https://github.com/elixir-mint/mint/commit/bd2a4e7513594997c140cfef9fe0e968712fb588"},{"type":"PACKAGE","url":"https://hex.pm/packages/mint"}],"affected":[{"package":{"name":"mint","ecosystem":"Hex","purl":"pkg:hex/mint"},"ranges":[{"type":"SEMVER","events":[{"introduced":"1.9.3"},{"fixed":"1.10.0"}]}],"versions":["1.9.3"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-82729.json"}},{"ranges":[{"type":"GIT","repo":"https://github.com/elixir-mint/mint","events":[{"introduced":"fc7d16538db7e40b56ed489f08683225cb0197fa"},{"fixed":"bd2a4e7513594997c140cfef9fe0e968712fb588"}]}],"versions":["v1.9.3"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-82729.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:L/SC:N/SI:N/SA:N"}],"credits":[{"name":"Tr3bor","type":"FINDER"},{"name":"Tr3bor","type":"REPORTER"},{"name":"Andrea Leopardi","type":"REMEDIATION_DEVELOPER"},{"name":"Jonatan Männchen / EEF","type":"COORDINATOR"}]}