{"id":"CVE-2026-59246","aliases":["EEF-CVE-2026-59246","EUVD-2026-43643","GHSA-8pf6-g464-h6h9"],"status":"published","title":"Zero-length HTTP/2 CONTINUATION frames bypass Mint's header-block byte-size cap and exhaust client memory","description":"Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service.\n\nThe Mint.HTTP2.handle_continuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headers_being_processed nesting, one level deeper per frame, and only releases it when a frame with the END_HEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assert_header_block_within_max_size/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits END_HEADERS, yet each frame still nests the accumulator one level deeper.\n\nA malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without END_HEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination.\n\nThis issue affects mint: from 0.1.0 before 1.9.2.","severity":{"version":"4.0","score":6.3,"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00502,"percentile":0.43283,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-770"],"published":"2026-07-14T08:37:04Z","modified":"2026-10-28T02:30:47Z","fixes":[{"ecosystem":"Hex","package":"mint","fixed_in":["1.9.2"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Hex","package":"mint","ranges":[{"type":"SEMVER","events":[{"introduced":"0.1.0"},{"fixed":"1.9.2"}]}],"versions":["0.1.0","0.2.0","0.2.1","0.3.0","0.4.0","0.5.0","1.0.0","1.1.0","1.2.0","1.2.1","1.3.0","1.4.0","1.4.1","1.4.2","1.5.0","1.5.1","1.5.2","1.6.0","1.6.1","1.6.2","1.7.0","1.7.1","1.8.0","1.9.0","1.9.1"]}],"products":[{"vendor":"elixir-mint","product":"mint"},{"vendor":"linuxmint","product":"mint"}],"references":[{"url":"https://github.com/elixir-mint/mint/security/advisories/GHSA-8pf6-g464-h6h9","tags":["vendor-advisory","related","exploit","advisory"]},{"url":"https://cna.erlef.org/cves/CVE-2026-59246.html","tags":["related","web"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-59246","tags":["related","web"]},{"url":"https://github.com/elixir-mint/mint/commit/5779de1666344b32aefc4354184ea07f902f73ce","tags":["patch","fix"]},{"url":"https://github.com","tags":["web"]},{"url":"https://repo.hex.pm","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59246.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59246","tags":["advisory"]},{"url":"https://github.com/elixir-mint/mint","tags":["package"]},{"url":"https://hex.pm/packages/mint","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-59246","title":"Zero-length HTTP/2 CONTINUATION frames bypass Mint's header-block byte-size cap and exhaust client memory","description":"Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service.\n\nThe Mint.HTTP2.handle_continuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headers_being_processed nesting, one level deeper per frame, and only releases it when a frame with the END_HEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assert_header_block_within_max_size/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits END_HEADERS, yet each frame still nests the accumulator one level deeper.\n\nA malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without END_HEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination.\n\nThis issue affects mint: from 0.1.0 before 1.9.2.","status":"published","published":"2026-07-14T08:37:04.609Z","modified":"2026-07-14T15:08:39.463Z","cvss":[{"version":"4.0","score":6.3,"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","level":"medium","assessor":"cna"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:19:58.560602Z"}],"euvd":[{"id":"EUVD-2026-43643","description":"Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service.\n\nThe Mint.HTTP2.handle_continuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headers_being_processed nesting, one level deeper per frame, and only releases it when a frame with the END_HEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assert_header_block_within_max_size/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits END_HEADERS, yet each frame still nests the accumulator one level deeper.\n\nA malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without END_HEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination.\n\nThis issue affects mint: from 0.1.0 before 1.9.2.","status":"published","published":"2026-07-14T08:37:04Z","modified":"2026-07-14T15:08:39Z","cvss":[{"version":"4.0","score":6.3,"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","level":"medium"}],"updated_at":"2026-11-02T18:19:59.713046Z"}],"nvd":[{"id":"CVE-2026-59246","description":"Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service.\n\nThe Mint.HTTP2.handle_continuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headers_being_processed nesting, one level deeper per frame, and only releases it when a frame with the END_HEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assert_header_block_within_max_size/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits END_HEADERS, yet each frame still nests the accumulator one level deeper.\n\nA malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without END_HEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination.\n\nThis issue affects mint: from 0.1.0 before 1.9.2.","status":"published","published":"2026-07-14T09:16:41.727Z","modified":"2026-10-24T21:10:00.13Z","cvss":[{"version":"4.0","score":6.3,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:12:29.114188Z"}],"osv":[{"id":"CVE-2026-59246","title":"Zero-length HTTP/2 CONTINUATION frames bypass Mint's header-block byte-size cap and exhaust client memory","description":"Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service.\n\nThe Mint.HTTP2.handle_continuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headers_being_processed nesting, one level deeper per frame, and only releases it when a frame with the END_HEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assert_header_block_within_max_size/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits END_HEADERS, yet each frame still nests the accumulator one level deeper.\n\nA malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without END_HEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination.\n\nThis issue affects mint: from 0.1.0 before 1.9.2.","status":"published","published":"2026-07-14T08:37:04.609Z","modified":"2026-10-28T02:30:47.76830594Z","cvss":[{"version":"4.0","score":6.3,"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","level":"medium"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:45:12.496548Z"},{"id":"EEF-CVE-2026-59246","title":"Zero-length HTTP/2 CONTINUATION frames bypass Mint's header-block byte-size cap and exhaust client memory","description":"## Summary\n\nAllocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service.\n\nThe Mint.HTTP2.handle\\_continuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headers\\_being\\_processed nesting, one level deeper per frame, and only releases it when a frame with the END\\_HEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assert\\_header\\_block\\_within\\_max\\_size/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits END\\_HEADERS, yet each frame still nests the accumulator one level deeper.\n\nA malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without END\\_HEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination.\n\nThis issue affects mint: from 0.1.0 before 1.9.2.","status":"published","published":"2026-07-14T08:37:04.609Z","modified":"2026-07-30T18:22:03.450604Z","cvss":[{"version":"4.0","score":6.3,"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","level":"medium"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:46:33.520522Z"}]}}