{"id":"CVE-2026-110499","revision":"f2ec9c0e33a9485ab0a748461ce20b30","records":[{"revision":"f2ec9c0e33a9485ab0a748461ce20b30","observedAt":"2026-10-26T16:35:30.797+00:00","statement":{"source":"cve-program","id":"CVE-2026-110499","aliases":[],"title":"Client-chosen HPACK encoder table size is applied uncapped, growing per-connection state with every response in Bandit","description":"Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/2 implementation of mtrudel bandit allows an unauthenticated remote attacker to grow per-connection memory and CPU cost without bound via a large SETTINGS_HEADER_TABLE_SIZE. Bandit resizes its HPACK encoder table to whatever size the client advertises, up to 2^32-1 bytes, and indexes response headers into it. Because responses carry distinct values such as date or content-length, nothing is evicted and the table grows with every response for the life of the connection, while each lookup scans it linearly.\n\nThe SETTINGS handling in Bandit.HTTP2.Connection (lib/bandit/http2/connection.ex) passes remote_settings.header_table_size to HPAX.resize/2 with no server-side cap, and encode_headers encodes every response header as :store. Serving N responses on one connection therefore costs O(N²) CPU in the connection process.\n\nThis issue affects bandit: from 0.3.6 before 1.14.0.","state":0,"publishedAt":"2026-10-26T13:32:38.613+00:00","modifiedAt":"2026-10-26T15:35:50.929+00:00","affected":[{"ecosystem":"https://repo.hex.pm","name":"bandit","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"collectionURL\": \"https://repo.hex.pm\",\n                    \"cpes\": [\n                        \"cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*\"\n                    ],\n                    \"defaultStatus\": \"unaffected\",\n                    \"packageName\": \"bandit\",\n                    \"packageURL\": \"pkg:hex/bandit\",\n                    \"product\": \"bandit\",\n                    \"repo\": \"https://github.com/mtrudel/bandit\",\n                    \"vendor\": \"mtrudel\",\n                    \"versions\": [\n                        {\n                            \"lessThan\": \"1.14.0\",\n                            \"status\": \"affected\",\n                            \"version\": \"0.3.6\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"},{"ecosystem":"https://github.com","name":"mtrudel/bandit","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"collectionURL\": \"https://github.com\",\n                    \"cpes\": [\n                        \"cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*\"\n                    ],\n                    \"defaultStatus\": \"unaffected\",\n                    \"packageName\": \"mtrudel/bandit\",\n                    \"packageURL\": \"pkg:github/mtrudel/bandit\",\n                    \"product\": \"bandit\",\n                    \"repo\": \"https://github.com/mtrudel/bandit\",\n                    \"vendor\": \"mtrudel\",\n                    \"versions\": [\n                        {\n                            \"lessThan\": \"220b9dfd27f9a21305be2afc75cbe585ddc24e7a\",\n                            \"status\": \"affected\",\n                            \"version\": \"0e68313fab9d204257ebad5c447e4cd9cea8e0ea\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","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","score":8.7,"severity":"HIGH"}],"references":["https://github.com/mtrudel/bandit/security/advisories/GHSA-47x4-3fxf-82fr","https://cna.erlef.org/cves/CVE-2026-110499.html","https://osv.dev/vulnerability/EEF-CVE-2026-110499","https://github.com/mtrudel/bandit/commit/0e68313fab9d204257ebad5c447e4cd9cea8e0ea","https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-110499","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-110499","identifiers":["CVE-2026-110499"]},"retained":false,"historicalAffected":[]}],"coverage":[]}