{"id":"CVE-2026-105297","revision":"d24d81ebbad841c2ad957f9fc8990e52","records":[{"revision":"d24d81ebbad841c2ad957f9fc8990e52","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-105297","aliases":[],"title":"Pingora HTTP/2 server memory exhaustion through unbounded default header-list and concurrent-stream limits","description":"Summary\n\n\n\nBefore version 0.8.1, Pingora's HTTP/2 server used the h2 crate's default limits unless the application set its own 16 MiB decoded header-list size and no limit on concurrent streams. 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\n\n\n\nImpact\n\n\n\nRemote, unauthenticated denial of service against 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\n\n\n\nNote that Cloudflare CDN customers were unaffected, as internal Pingora services at Cloudflare do not have HTTP/2 clients.\n\n\n\nMitigation:\n\n  *  \n\nUpgrade to pingora 0.8.1 or later (fix:  https://github.com/cloudflare/pingora/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.\n\n\n  *  \n\nApplications that supply their own H2Options are not covered by these defaults and must set max_header_list_size and max_concurrent_streams explicitly (this also works on versions before 0.8.1), or, on 0.8.1 and later, start from pingora_core::protocols::http::v2::server::default_h2_options(). H2Options::default() does not include these limits.","state":0,"publishedAt":"2026-10-20T00:40:27.3+00:00","modifiedAt":"2026-10-20T19:20:35.542+00:00","affected":[{"ecosystem":"Vendor product","name":"https://github.com/cloudflare/pingora","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Cloudflare\",\n                    \"product\": \"https://github.com/cloudflare/pingora\",\n                    \"repo\": \"https://github.com/cloudflare/pingora\",\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"0.1.0\",\n                            \"lessThan\": \"0.8.1\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://github.com/cloudflare/pingora"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-105297","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-105297","identifiers":["CVE-2026-105297"]},"retained":false,"historicalAffected":[]}],"coverage":[]}