{"id":"CVE-2026-113436","title":"Quadratic bignum parsing of Content-Length and Host port values in Bandit","summary":"Inefficient Algorithmic Complexity vulnerability in the header integer parser of mtrudel bandit allows an unauthenticated remote attacker to consume server CPU via a content-length value or a Host or :authority port made of thousands of …","severity":"high","cvss":8.7,"cvssVector":"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","cvssSource":"cna","cwe":["CWE-407"],"vendor":"mtrudel","product":"bandit","affected":["bandit >= 1.0.0-pre.7 < 1.14.0","mtrudel/bandit >= e0c8c0c30af9b0f57d8aafac37ddd9294363a8be < 220b9dfd27f9a21305be2afc75cbe585ddc24e7a"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-26T15:12:04.626946Z"},"published":"2026-10-26","updated":"2026-10-26","sourceUpdated":"2026-10-26T15:35:51.556Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-113436","references":[{"url":"https://github.com/mtrudel/bandit/security/advisories/GHSA-29cr-8477-rg6r","label":"Quadratic bignum parsing of Content-Length and Host port values in Bandit"},{"url":"https://cna.erlef.org/cves/CVE-2026-113436.html","label":"EEF CNA record for CVE-2026-113436"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-113436","label":"OSV record EEF-CVE-2026-113436"},{"url":"https://github.com/mtrudel/bandit/commit/e0c8c0c30af9b0f57d8aafac37ddd9294363a8be","label":"Introducing commit e0c8c0c in mtrudel/bandit"},{"url":"https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a","label":"Fix commit 220b9df in mtrudel/bandit"}],"tags":["cve.org"],"ingestedAt":"2026-10-26T14:27:31.820Z","epss":0.00602,"epssPercentile":0.48611,"slug":"CVE-2026-113436","body":"## Overview\n\nInefficient Algorithmic Complexity vulnerability in the header integer parser of mtrudel bandit allows an unauthenticated remote attacker to consume server CPU via a content-length value or a Host or :authority port made of thousands of digits.\n\nBandit.Headers.parse_integer/2 in lib/bandit/headers.ex builds the number one digit at a time with no limit on the digit count, allocating a new bignum at each step, so one value costs time quadratic in its length. It runs on raw request input over HTTP/1 and HTTP/2, before any range check. Over HTTP/2, a 4,000-digit value can be stored once in the HPACK dynamic table and re-sent on each new stream for about one byte: 124 KB of traffic kept the server busy for 27.9 s.\n\nThis issue affects bandit: from 1.0.0-pre.7 before 1.14.0.\n\n## Affected\n\n- `bandit >= 1.0.0-pre.7 < 1.14.0`\n- `mtrudel/bandit >= e0c8c0c30af9b0f57d8aafac37ddd9294363a8be < 220b9dfd27f9a21305be2afc75cbe585ddc24e7a`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":47.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}