{"id":"CVE-2026-59246","summary":"Zero-length HTTP/2 CONTINUATION frames bypass Mint's header-block byte-size cap and exhaust client memory","details":"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.","aliases":["EEF-CVE-2026-59246","GHSA-8pf6-g464-h6h9"],"modified":"2026-07-19T03:46:50.514105584Z","published":"2026-07-14T08:37:04.609Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59246.json","unresolved_ranges":[{"extracted_events":[{"introduced":"596ca4304504be68939c4929e0831557097962b8"},{"fixed":"5779de1666344b32aefc4354184ea07f902f73ce"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"EEF","cwe_ids":["CWE-770"]},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-59246.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-59246"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59246.json"},{"type":"ADVISORY","url":"https://github.com/elixir-mint/mint/security/advisories/GHSA-8pf6-g464-h6h9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59246"},{"type":"FIX","url":"https://github.com/elixir-mint/mint/commit/5779de1666344b32aefc4354184ea07f902f73ce"},{"type":"PACKAGE","url":"https://github.com/elixir-mint/mint"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/elixir-mint/mint","events":[{"introduced":"47889857fb36f07606ad9c2e52080d202d419058"},{"fixed":"d066c6685dca58fceb2e22e97a9266866b622bfc"},{"fixed":"5779de1666344b32aefc4354184ea07f902f73ce"}],"database_specific":{"extracted_events":[{"introduced":"0.1.0"},{"fixed":"1.9.2"}],"source":["DESCRIPTION","REFERENCES"]}}],"versions":["v1.9.1","v1.9.0","v1.8.0","v1.7.1","v1.7.0","v1.6.2","v1.6.1","v1.6.0","v1.5.2","v1.5.1","v1.5.0","v1.4.2","v1.4.1","v1.4.0","v1.3.0","v1.2.1","v1.2.0","v1.1.0","v1.0.0","v0.5.0","v0.4.0","v0.2.1","v0.2.0","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59246.json"}}],"schema_version":"1.7.5","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"}]}