{"schema":"threatline.record/2","record":{"id":"CVE-2026-78659","aliases":[],"summary":"HTTP/2 server memory exhaustion due to Trailer headers in net/http","details":"When \"Trailer\" headers are sent by a client, the HTTP server internally uses the header values to populate the Request.Trailer map passed to the server handler. Because Request.Trailer is a map, each entry incurs memory overhead. For HTTP/2 servers, a malicious client can exploit this by sending a \"Trailer\" header that declares a large number of fields, causing the server to allocate a disproportionate amount of memory while bypassing Server.MaxHeaderValueCount and Server.MaxHeaderBytes limits. This exploit is not applicable for HTTP/1 servers, which do not support multiplexing a large number of requests over one TCP connection, and whose Server.MaxHeaderBytes are calculated differently.","categories":["Unclassified"],"product":"net/http","vendor":"Go standard library","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-78659","source_modified_at":"2026-10-09T15:34:24.199Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"net/http","vendor":"Go standard library","versions":[{"version":"0","lessThan":"1.26.9","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-78659","source_modified_at":"2026-10-09T15:34:24.199Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"net/http/internal/http2","vendor":"Go standard library","versions":[{"version":"1.27.0-0","lessThan":"1.27.2","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-78659","source_modified_at":"2026-10-09T15:34:24.199Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"golang.org/x/net/http2","vendor":"golang.org/x/net","versions":[{"version":"0","lessThan":"0.60.0","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-78659","source_modified_at":"2026-10-09T15:34:24.199Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"net/http","ecosystem":null},"version":"1.26.9","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-78659","source_modified_at":"2026-10-09T15:34:24.199Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"net/http/internal/http2","ecosystem":null},"version":"1.27.2","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-78659","source_modified_at":"2026-10-09T15:34:24.199Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"golang.org/x/net/http2","ecosystem":null},"version":"0.60.0","basis":"first unaffected version stated in the CVE record"}],"cvss":7.5,"severity":"High","kev":{"listed":false},"epss":{"probability":0.0057,"percentile":0.46497,"score_date":"2026-10-23"},"published_at":"2026-10-08T22:53:58.192Z","modified_at":"2026-10-09T15:34:24.199Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-78659","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-09T15:34:24.199Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-78659","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://go.dev/cl/847185"},{"source":"CVE List","url":"https://go.dev/cl/847314"},{"source":"CVE List","url":"https://go.dev/issue/81857"},{"source":"CVE List","url":"https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"},{"source":"CVE List","url":"https://groups.google.com/g/golang-announce/c/ZPwCyRUuGBs"},{"source":"CVE List","url":"https://pkg.go.dev/vuln/GO-2026-6603"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CISA ADP","ssvc":{"exploitation":"none","automatable":"yes","technical_impact":"partial","assessed_at":"2026-10-09T15:27:33.510545Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-09T15:34:24.199Z","content_hash":"88cea3580c8c5f89ac0fa2826d85b579a6ce95d668a315042ff56e5973983f2b"}}