{"id":"CVE-2026-82729","state":"PUBLISHED","title":"Quadratic chunk-size parsing in Mint.HTTP1.Parse allows CPU-exhaustion DoS","description":"Inefficient 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\nparse_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.","publishedAt":"2026-09-04T14:31:20.562Z","updatedAt":"2026-09-04T19:33:32.398Z","severity":{"score":6.3,"label":"Medium","version":"4.0","vector":"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","source":"EEF"},"assigner":"EEF","products":["elixir-mint mint"],"affected":[{"vendor":"elixir-mint","product":"mint","packageName":"mint","packageURL":"pkg:hex/mint","defaultStatus":"unaffected","versions":[{"version":"1.9.3","status":"affected","lessThan":"1.10.0","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"],"modules":["'Elixir.Mint.HTTP1.Parse'","'Elixir.Mint.HTTP1'"],"programFiles":["lib/mint/http1/parse.ex","lib/mint/http1.ex"],"programRoutines":[{"name":"'Elixir.Mint.HTTP1.Parse':chunk_size/1"},{"name":"'Elixir.Mint.HTTP1':decode_body/5"}],"repo":"https://github.com/elixir-mint/mint"},{"vendor":"elixir-mint","product":"mint","packageName":"elixir-mint/mint","packageURL":"pkg:github/elixir-mint/mint","defaultStatus":"unaffected","versions":[{"version":"fc7d16538db7e40b56ed489f08683225cb0197fa","status":"affected","lessThan":"bd2a4e7513594997c140cfef9fe0e968712fb588","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"],"modules":["'Elixir.Mint.HTTP1.Parse'","'Elixir.Mint.HTTP1'"],"programFiles":["lib/mint/http1/parse.ex","lib/mint/http1.ex"],"programRoutines":[{"name":"'Elixir.Mint.HTTP1.Parse':chunk_size/1"},{"name":"'Elixir.Mint.HTTP1':decode_body/5"}],"repo":"https://github.com/elixir-mint/mint"}],"references":["https://github.com/elixir-mint/mint/security/advisories/GHSA-7p8w-j234-7qc8","https://cna.erlef.org/cves/CVE-2026-82729.html","https://osv.dev/vulnerability/EEF-CVE-2026-82729","https://github.com/elixir-mint/mint/commit/bd2a4e7513594997c140cfef9fe0e968712fb588"],"weaknesses":["CWE-407"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/82xxx/CVE-2026-82729.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-82729","state":"PUBLISHED","datePublished":"2026-09-04T14:31:20.562Z","dateUpdated":"2026-09-04T19:33:32.398Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-08-31T00:59:08.960Z"},"containers":{"cna":{"title":"Quadratic chunk-size parsing in Mint.HTTP1.Parse allows CPU-exhaustion DoS","descriptions":[{"lang":"en","value":"Inefficient 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\nparse_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."}],"affected":[{"vendor":"elixir-mint","product":"mint","packageName":"mint","packageURL":"pkg:hex/mint","defaultStatus":"unaffected","versions":[{"version":"1.9.3","status":"affected","lessThan":"1.10.0","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"],"modules":["'Elixir.Mint.HTTP1.Parse'","'Elixir.Mint.HTTP1'"],"programFiles":["lib/mint/http1/parse.ex","lib/mint/http1.ex"],"programRoutines":[{"name":"'Elixir.Mint.HTTP1.Parse':chunk_size/1"},{"name":"'Elixir.Mint.HTTP1':decode_body/5"}],"repo":"https://github.com/elixir-mint/mint"},{"vendor":"elixir-mint","product":"mint","packageName":"elixir-mint/mint","packageURL":"pkg:github/elixir-mint/mint","defaultStatus":"unaffected","versions":[{"version":"fc7d16538db7e40b56ed489f08683225cb0197fa","status":"affected","lessThan":"bd2a4e7513594997c140cfef9fe0e968712fb588","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"],"modules":["'Elixir.Mint.HTTP1.Parse'","'Elixir.Mint.HTTP1'"],"programFiles":["lib/mint/http1/parse.ex","lib/mint/http1.ex"],"programRoutines":[{"name":"'Elixir.Mint.HTTP1.Parse':chunk_size/1"},{"name":"'Elixir.Mint.HTTP1':decode_body/5"}],"repo":"https://github.com/elixir-mint/mint"}],"references":[{"url":"https://github.com/elixir-mint/mint/security/advisories/GHSA-7p8w-j234-7qc8","tags":["related","vendor-advisory"]},{"url":"https://cna.erlef.org/cves/CVE-2026-82729.html","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-82729","tags":["related"]},{"url":"https://github.com/elixir-mint/mint/commit/bd2a4e7513594997c140cfef9fe0e968712fb588","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":6.3,"baseSeverity":"MEDIUM","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"LOW","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-407","description":"CWE-407 Inefficient Algorithmic Complexity","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-09-04T14:31:20.562Z"},"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*","versionEndExcluding":"1.10.0","versionStartIncluding":"1.9.3","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"finder","value":"Tr3bor"},{"lang":"en","type":"reporter","value":"Tr3bor"},{"lang":"en","type":"remediation developer","value":"Andrea Leopardi"},{"lang":"en","type":"coordinator","value":"Jonatan Männchen / EEF"}],"impacts":[{"capecId":"CAPEC-130","descriptions":[{"lang":"en","value":"CAPEC-130 Excessive Allocation"}]}],"source":{"discovery":"EXTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/elixir-mint/mint/security/advisories/GHSA-7p8w-j234-7qc8","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-04T19:33:08.928597Z","id":"CVE-2026-82729","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-04T19:33:32.398Z"}}]}}}