{"id":"CVE-2026-78660","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-78660","generatedAt":"2026-10-28T01:50:41.158Z","title":"Historically, we have been rather lax about malformed framing-related headers in our HTTP/2 implementation, as they cannot interfere with HTTP/2 framing.","description":"Historically, we have been rather lax about malformed framing-related headers in our HTTP/2 implementation, as they cannot interfere with HTTP/2 framing. However, this makes it possible for our HTTP/2 implementation to forward responses containing such headers to an HTTP/1 client when acting as a reverse proxy. If the HTTP/1 client also does not behave strictly enough, this can result in response smuggling.","published":"2026-10-08T23:17:04.000Z","lastModified":"2026-10-09T17:16:49.000Z","status":"Awaiting Analysis","sourceIdentifier":"security@golang.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},"cwe":["CWE-444"],"affected":[],"epss":{"score":0.00425,"percentile":0.36558,"date":"2026-10-26","history":[{"date":"2026-10-09","score":0.00188,"percentile":0.07727}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"scored","label":"Newly scored","at":"2026-10-09T19:00:22.000Z","detail":{"from":null,"score":"7.5","severity":"HIGH","fromSeverity":null},"summary":"Now scored CVSS 7.5 HIGH."},{"kind":"new","label":"New CVE","at":"2026-10-08T23:17:04.000Z","detail":{"score":null,"severity":null,"publishedAt":"2026-10-08T23:17:03.510Z"},"summary":"New CVE, high severity (CVSS 7.5)."}],"references":[{"url":"https://go.dev/cl/835145","source":"security@golang.org"},{"url":"https://go.dev/cl/836385","source":"security@golang.org"},{"url":"https://go.dev/issue/81115","source":"security@golang.org"},{"url":"https://groups.google.com/g/golang-announce/c/U2fTuyDJznI","source":"security@golang.org"},{"url":"https://pkg.go.dev/vuln/GO-2026-6610","source":"security@golang.org"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-78660","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}