{"schema":"threatline.record/2","record":{"id":"CVE-2026-105297","aliases":[],"summary":"Pingora HTTP/2 server memory exhaustion through unbounded default header-list and concurrent-stream limits","details":"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.","categories":["Unclassified"],"product":"https://github.com/cloudflare/pingora","vendor":"Cloudflare","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-105297","source_modified_at":"2026-10-20T19:20:35.542Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"https://github.com/cloudflare/pingora","vendor":"Cloudflare","versions":[{"status":"affected","version":"0.1.0","lessThan":"0.8.1","versionType":"semver"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-105297","source_modified_at":"2026-10-20T19:20:35.542Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"https://github.com/cloudflare/pingora","ecosystem":null},"version":"0.8.1","basis":"first unaffected version stated in the CVE record"}],"cvss":7.5,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00338,"percentile":0.26061,"score_date":"2026-10-23"},"published_at":"2026-10-20T00:40:27.300Z","modified_at":"2026-10-20T19:20:35.542Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-105297","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-20T19:20:35.542Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-105297","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/cloudflare/pingora"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"none","automatable":"yes","technical_impact":"partial","assessed_at":"2026-10-20T19:20:25.097096Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-20T19:20:35.542Z","content_hash":"425a53ca9b2d0a5addab75907a0c94e96ea81db4b146bbb51167957e46c3250a"}}