{"id":"RUSTSEC-2026-0389","summary":"Pingora HTTP/2 server memory exhaustion through unbounded default header-list and concurrent-stream limits","details":"Pingora versions prior to 0.8.1 used the h2 crate's default HTTP/2 server limits, a 16 MiB decoded header-list size and no limit on concurrent streams, unless the application set its own. A remote, unauthenticated client can send 1-byte HPACK references to a near-empty header, making the server allocate hundreds of thousands of header fields per stream across an unlimited number of streams on one connection, and use HTTP/2 flow control to keep those streams open. This can exhaust memory and degrade or terminate the Pingora process.\n\nThis affects any Pingora service that terminates HTTP/2 (h2 or h2c) without explicitly setting `max_header_list_size` and `max_concurrent_streams`. The reporter showed that a single connection could get a Pingora process with a 2 GiB memory limit OOM-killed.\n\nThis flaw was corrected in commit d193c8d49b8b7c1c1ede93183759caa4f6906bbd. When no `H2Options` are supplied, Pingora now advertises and enforces a 64 KiB decoded header-list limit and at most 100 concurrent streams per connection. Users should upgrade to Pingora \u003e= 0.8.1. Applications that supply their own `H2Options` are not covered by these defaults and must set `max_header_list_size` and `max_concurrent_streams` explicitly, or start from `pingora_core::protocols::http::v2::server::default_h2_options()`. `H2Options::default()` does not include these limits.\n\nNote: Cloudflare CDN customers were unaffected, as internal Pingora services at Cloudflare do not have HTTP/2 clients.","aliases":["CVE-2026-105297","GHSA-7gpj-mj4q-x62x"],"modified":"2026-10-26T11:15:11.357540777Z","published":"2026-10-20T12:00:00Z","database_specific":{"license":"CC0-1.0"},"references":[{"type":"PACKAGE","url":"https://crates.io/crates/pingora-core"},{"type":"ADVISORY","url":"https://rustsec.org/advisories/RUSTSEC-2026-0389.html"},{"type":"WEB","url":"https://github.com/cloudflare/pingora/commit/d193c8d49b8b7c1c1ede93183759caa4f6906bbd"}],"affected":[{"package":{"name":"pingora-core","ecosystem":"crates.io","purl":"pkg:cargo/pingora-core"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"0.8.1"}]}],"ecosystem_specific":{"affected_functions":null,"affects":{"arch":[],"os":[],"functions":[]}},"database_specific":{"categories":["denial-of-service"],"cvss":"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","informational":null,"source":"https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0389.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}