{"id":"EUVD-2026-95421","revision":"008edf6bba184896a0efff60edf16c5b","records":[{"revision":"008edf6bba184896a0efff60edf16c5b","observedAt":"2026-11-03T11:09:44.295+00:00","statement":{"source":"euvd","id":"EUVD-2026-95421","aliases":["CVE-2026-56866","GHSA-f5vf-8pvc-394g"],"title":"When http.Transport sends an HTTP/1 CONNECT request with a non-empty Request.Body, it writes the body directly to the connection without framing after the request headers. If the server rejects the CONNECT request with a non-2xx keep-alive …","description":"When http.Transport sends an HTTP/1 CONNECT request with a non-empty Request.Body, it writes the body directly to the connection without framing after the request headers. If the server rejects the CONNECT request with a non-2xx keep-alive response, Transport returns the connection to the idle pool. Because CONNECT requests do not have a request body, the server may interpret the trailing body bytes as a subsequent pipelined HTTP/1.1 request on the connection, leaving the pooled connection desynchronized and causing the next caller that reuses it to read the response to the injected request. In reverse proxies (including httputil.ReverseProxy) that forward CONNECT requests through a shared Transport, this can lead to cross-user response poisoning.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5,"severity":null}],"references":["https://go.dev/cl/847306","https://go.dev/issue/81740","https://groups.google.com/g/golang-announce/c/U2fTuyDJznI","https://pkg.go.dev/vuln/GO-2026-6605"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-95421","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Oct 8, 2026, 10:53:58 PM","dateUpdated":"Oct 9, 2026, 3:54:59 PM"},"relatedAdvisories":[{"id":"SUSE-SU-2026:24239-1","title":"Security update for go1.26","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78667","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032"]},{"id":"openSUSE-SU-2026:22093-1","title":"Security update for go1.27","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032"]},{"id":"RHSA-2026:92509","title":"Red Hat Security Advisory: Red Hat OpenShift Service Mesh 3.3.9","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"openSUSE-SU-2026:22095-1","title":"Security update for go1.26","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78667","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032"]},{"id":"openSUSE-SU-2026:12093-1","title":"go1.26-1.26.9-1.1 on GA media","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78667","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032"]},{"id":"openSUSE-SU-2026:12112-1","title":"rclone-1.75.2-1.1 on GA media","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-84445","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032"]},{"id":"RHSA-2026:87043","title":"Red Hat Security Advisory: golang security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:92497","title":"Red Hat Security Advisory: Red Hat OpenShift Service Mesh 3.2.11","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:86196","title":"Red Hat Security Advisory: golang security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"openSUSE-SU-2026:12101-1","title":"go1.27-1.27.2-1.1 on GA media","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032"]},{"id":"WID-SEC-W-2026-3841","title":"Golang Go: Mehrere Schwachstellen","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032"]},{"id":"RHSA-2026:86093","title":"Red Hat Security Advisory: golang security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:87246","title":"Red Hat Security Advisory: go-toolset:rhel8 security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2024-45336","CVE-2025-4673","CVE-2025-22866","CVE-2025-22874","CVE-2025-68121","CVE-2026-27137","CVE-2026-27143","CVE-2026-27144","CVE-2026-27145","CVE-2026-32280","CVE-2026-32281","CVE-2026-32282","CVE-2026-32283","CVE-2026-33810","CVE-2026-33811","CVE-2026-33814","CVE-2026-33818","CVE-2026-39820","CVE-2026-39821","CVE-2026-42499","CVE-2026-42504","CVE-2026-56853","CVE-2026-56858","CVE-2026-56859","CVE-2026-56860","CVE-2026-56862","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:92480","title":"Red Hat Security Advisory: Red Hat OpenShift Service Mesh 3.1.14","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:87041","title":"Red Hat Security Advisory: golang security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:92516","title":"Red Hat Security Advisory: Red Hat OpenShift Service Mesh 3.4.4","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:87245","title":"Red Hat Security Advisory: go-toolset:rhel8 security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2024-45336","CVE-2025-4673","CVE-2025-22866","CVE-2025-22874","CVE-2025-68121","CVE-2026-27137","CVE-2026-27143","CVE-2026-27144","CVE-2026-27145","CVE-2026-32280","CVE-2026-32281","CVE-2026-32282","CVE-2026-32283","CVE-2026-33810","CVE-2026-33811","CVE-2026-33814","CVE-2026-33818","CVE-2026-39820","CVE-2026-39821","CVE-2026-42499","CVE-2026-42504","CVE-2026-56853","CVE-2026-56858","CVE-2026-56859","CVE-2026-56860","CVE-2026-56862","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:86203","title":"Red Hat Security Advisory: go-toolset:rhel8 security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:87042","title":"Red Hat Security Advisory: golang security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:90994","title":"Red Hat Security Advisory: go-toolset:rhel8 security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2024-45336","CVE-2025-22866","CVE-2025-22874","CVE-2025-68121","CVE-2026-27137","CVE-2026-27143","CVE-2026-27144","CVE-2026-27145","CVE-2026-32280","CVE-2026-32281","CVE-2026-32282","CVE-2026-32283","CVE-2026-33810","CVE-2026-33811","CVE-2026-33814","CVE-2026-33818","CVE-2026-39820","CVE-2026-39821","CVE-2026-42499","CVE-2026-42504","CVE-2026-56853","CVE-2026-56858","CVE-2026-56859","CVE-2026-56860","CVE-2026-56862","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"RHSA-2026:87040","title":"Red Hat Security Advisory: golang security, bug fix, and enhancement update","vulnerabilityIds":["CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]},{"id":"msrc_CVE-2026-56866","title":"HTTP/1 client connection desynchronization after CONNECT rejection in net/http","vulnerabilityIds":["CVE-2026-56866"]},{"id":"SUSE-SU-2026:24237-1","title":"Security update for go1.27","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78659","CVE-2026-78660","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94444","CVE-2026-94447","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032"]},{"id":"RHSA-2026:92451","title":"Red Hat Security Advisory: Red Hat OpenShift Service Mesh 3.0.17","vulnerabilityIds":["CVE-2026-56857","CVE-2026-56866","CVE-2026-78663","CVE-2026-78667","CVE-2026-78669","CVE-2026-94439","CVE-2026-94440","CVE-2026-94448","CVE-2026-97030","CVE-2026-97031","CVE-2026-97032","CVE-2026-111943"]}],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-95421","identifiers":["EUVD-2026-95421","CVE-2026-56866","GHSA-f5vf-8pvc-394g"]},"retained":false,"historicalAffected":[]}],"coverage":[]}