{"id":"CVE-2026-56853","aliases":["GO-2026-6089","BIT-golang-2026-56853"],"title":"Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http","summary":"Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"stdlib","product":"stdlib","ecosystem":"go","affected":["stdlib >= 1.27.0-0, < 1.27.0-rc.3"],"patched":["stdlib 1.27.0-rc.3"],"published":"2026-08-13","updated":"2026-10-07","sourceUpdated":"2026-10-07T10:41:45.889550693Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GO-2026-6089","references":[{"url":"https://go.dev/issue/80205"},{"url":"https://go.dev/cl/795540"},{"url":"https://groups.google.com/g/golang-announce/c/94pEornpRlI"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56853.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-56853"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2515827"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-56853"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56853"},{"url":"https://pkg.go.dev/vuln/GO-2026-6089"},{"url":"https://access.redhat.com/errata/RHSA-2026:71113"},{"url":"https://access.redhat.com/errata/RHSA-2026:71112"},{"url":"https://access.redhat.com/errata/RHSA-2026:68334"},{"url":"https://access.redhat.com/errata/RHSA-2026:68335"},{"url":"https://access.redhat.com/errata/RHSA-2026:71114"},{"url":"https://access.redhat.com/errata/RHSA-2026:65918"},{"url":"https://access.redhat.com/errata/RHSA-2026:61882"},{"url":"https://access.redhat.com/errata/RHSA-2026:67517"},{"url":"https://access.redhat.com/errata/RHSA-2026:66459"},{"url":"https://access.redhat.com/errata/RHSA-2026:65335"},{"url":"https://access.redhat.com/errata/RHSA-2026:67974"},{"url":"https://access.redhat.com/errata/RHSA-2026:66327"},{"url":"https://access.redhat.com/errata/RHSA-2026:70103"},{"url":"https://access.redhat.com/errata/RHSA-2026:63332"},{"url":"https://access.redhat.com/errata/RHSA-2026:64777"},{"url":"https://access.redhat.com/errata/RHSA-2026:62578"},{"url":"https://access.redhat.com/errata/RHSA-2026:60306"},{"url":"https://access.redhat.com/errata/RHSA-2026:63022"},{"url":"https://access.redhat.com/errata/RHSA-2026:63119"},{"url":"https://access.redhat.com/errata/RHSA-2026:65534"},{"url":"https://access.redhat.com/errata/RHSA-2026:62631"},{"url":"https://access.redhat.com/errata/RHSA-2026:65116"},{"url":"https://access.redhat.com/errata/RHSA-2026:65895"},{"url":"https://access.redhat.com/errata/RHSA-2026:70201"},{"url":"https://access.redhat.com/errata/RHSA-2026:67464"},{"url":"https://access.redhat.com/errata/RHSA-2026:64818"},{"url":"https://access.redhat.com/errata/RHSA-2026:63163"},{"url":"https://access.redhat.com/errata/RHSA-2026:60305"},{"url":"https://access.redhat.com/errata/RHSA-2026:62407"},{"url":"https://access.redhat.com/errata/RHSA-2026:63124"},{"url":"https://access.redhat.com/errata/RHSA-2026:66016"},{"url":"https://access.redhat.com/errata/RHSA-2026:64786"},{"url":"https://access.redhat.com/errata/RHSA-2026:62602"},{"url":"https://access.redhat.com/errata/RHSA-2026:65359"},{"url":"https://access.redhat.com/errata/RHSA-2026:62754"},{"url":"https://access.redhat.com/errata/RHSA-2026:62405"}],"tags":["osv","go","csaf","vex","red-hat"],"epss":0.00568,"epssPercentile":0.46877,"cvssSource":"vendor","cwe":["CWE-770"],"ingestedAt":"2026-08-14T19:18:46.559Z","slug":"CVE-2026-56853","body":"## Overview\n\nWhen a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this.\n\n## Affected packages\n\n- `stdlib >= 1.27.0-0, < 1.27.0-rc.3`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `stdlib 1.27.0-rc.3`\n\n## Vendor advisories\n\n- **RHSA-2026:71113** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.6 for RHEL 10, Red Hat Ansible Automation Platform 2.6 for RHEL 9 · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:71113)\n- **RHSA-2026:71112** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.7 for RHEL 10, Red Hat Ansible Automation Platform 2.7 for RHEL 9 · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:71112)\n- **RHSA-2026:68334** · Red Hat · fixed in: RHEM 1.1 for RHEL 10, RHEM 1.1 for RHEL 9 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68334)\n- **RHSA-2026:68335** · Red Hat · fixed in: RHEM 1.2 for RHEL 10, RHEM 1.2 for RHEL 9 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68335)\n- **RHSA-2026:71114** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.5 for RHEL 8, Red Hat Ansible Automation Platform 2.5 for RHEL 9 · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:71114)\n- **RHSA-2026:65918** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:65918)\n- **RHSA-2026:61882** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:61882)\n- **RHSA-2026:67517** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67517)\n- **RHSA-2026:66459** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:66459)\n- **RHSA-2026:65335** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:65335)\n- **RHSA-2026:67974** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:67974)\n- **Red Hat VEX** · Important · affected: Assisted Installer for Red Hat OpenShift Container Platform 2, AWS Load Balancer Operator, cert-manager Operator for Red Hat OpenShift, Compliance Operator, Confidential Compute Attestation, Deployment Validation Operator, … · no fix planned: Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat AI Inference Server, Red Hat Ansible Automation Platform 2, Red Hat Enterprise Linux 10, … · updated 2026-09-28 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56853.json)\n- **RHSA-2026:66327** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:66327)\n- **RHSA-2026:70103** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:70103)\n- **RHSA-2026:63332** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-09-04 · [advisory](https://access.redhat.com/errata/RHSA-2026:63332)\n- **RHSA-2026:64777** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-09-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:64777)\n- **RHSA-2026:62578** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-09-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:62578)\n- **RHSA-2026:60306** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-08-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:60306)\n- **RHSA-2026:63022** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63022)\n- **RHSA-2026:63119** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63119)\n- **RHSA-2026:65534** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-09-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:65534)\n- **RHSA-2026:62631** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-09-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:62631)\n- **RHSA-2026:65116** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-09-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:65116)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":201793,"id":"CVE-2026-56853","ts":1789399725843,"field":"cvss","old":null,"new":"7.5"},{"seq":201792,"id":"CVE-2026-56853","ts":1789399725843,"field":"severity","old":"none","new":"high"},{"seq":200523,"id":"CVE-2026-56853","ts":1789397373769,"field":"cvss","old":"7.5","new":null},{"seq":200522,"id":"CVE-2026-56853","ts":1789397373769,"field":"severity","old":"high","new":"none"},{"seq":198440,"id":"CVE-2026-56853","ts":1789391968790,"field":"cvss","old":null,"new":"7.5"},{"seq":198439,"id":"CVE-2026-56853","ts":1789391968790,"field":"severity","old":"none","new":"high"},{"seq":196233,"id":"CVE-2026-56853","ts":1789383585195,"field":"cvss","old":"7.5","new":null},{"seq":196232,"id":"CVE-2026-56853","ts":1789383585195,"field":"severity","old":"high","new":"none"},{"seq":195162,"id":"CVE-2026-56853","ts":1789380475038,"field":"cvss","old":null,"new":"7.5"},{"seq":195161,"id":"CVE-2026-56853","ts":1789380475038,"field":"severity","old":"none","new":"high"},{"seq":193949,"id":"CVE-2026-56853","ts":1789378515348,"field":"cvss","old":"7.5","new":null},{"seq":193948,"id":"CVE-2026-56853","ts":1789378515348,"field":"severity","old":"high","new":"none"},{"seq":192736,"id":"CVE-2026-56853","ts":1789376407124,"field":"cvss","old":null,"new":"7.5"},{"seq":192735,"id":"CVE-2026-56853","ts":1789376407124,"field":"severity","old":"none","new":"high"},{"seq":191523,"id":"CVE-2026-56853","ts":1789373419681,"field":"cvss","old":"7.5","new":null},{"seq":191522,"id":"CVE-2026-56853","ts":1789373419681,"field":"severity","old":"high","new":"none"},{"seq":190308,"id":"CVE-2026-56853","ts":1789369299987,"field":"cvss","old":null,"new":"7.5"},{"seq":190307,"id":"CVE-2026-56853","ts":1789369299987,"field":"severity","old":"none","new":"high"},{"seq":189095,"id":"CVE-2026-56853","ts":1789368266951,"field":"cvss","old":"7.5","new":null},{"seq":189094,"id":"CVE-2026-56853","ts":1789368266951,"field":"severity","old":"high","new":"none"},{"seq":187878,"id":"CVE-2026-56853","ts":1789365143337,"field":"cvss","old":null,"new":"7.5"},{"seq":187877,"id":"CVE-2026-56853","ts":1789365143337,"field":"severity","old":"none","new":"high"},{"seq":186665,"id":"CVE-2026-56853","ts":1789363271388,"field":"cvss","old":"7.5","new":null},{"seq":186664,"id":"CVE-2026-56853","ts":1789363271388,"field":"severity","old":"high","new":"none"},{"seq":185451,"id":"CVE-2026-56853","ts":1789361101317,"field":"cvss","old":null,"new":"7.5"},{"seq":185450,"id":"CVE-2026-56853","ts":1789361101317,"field":"severity","old":"none","new":"high"},{"seq":184238,"id":"CVE-2026-56853","ts":1789358155653,"field":"cvss","old":"7.5","new":null},{"seq":184237,"id":"CVE-2026-56853","ts":1789358155653,"field":"severity","old":"high","new":"none"},{"seq":182489,"id":"CVE-2026-56853","ts":1789354222458,"field":"cvss","old":null,"new":"7.5"},{"seq":182488,"id":"CVE-2026-56853","ts":1789354222458,"field":"severity","old":"none","new":"high"},{"seq":181282,"id":"CVE-2026-56853","ts":1789353120592,"field":"cvss","old":"7.5","new":null},{"seq":181281,"id":"CVE-2026-56853","ts":1789353120592,"field":"severity","old":"high","new":"none"},{"seq":180075,"id":"CVE-2026-56853","ts":1789350169109,"field":"cvss","old":null,"new":"7.5"},{"seq":180074,"id":"CVE-2026-56853","ts":1789350169109,"field":"severity","old":"none","new":"high"},{"seq":178868,"id":"CVE-2026-56853","ts":1789348101381,"field":"cvss","old":"7.5","new":null},{"seq":178867,"id":"CVE-2026-56853","ts":1789348101381,"field":"severity","old":"high","new":"none"},{"seq":177661,"id":"CVE-2026-56853","ts":1789346277606,"field":"cvss","old":null,"new":"7.5"},{"seq":177660,"id":"CVE-2026-56853","ts":1789346277606,"field":"severity","old":"none","new":"high"},{"seq":176454,"id":"CVE-2026-56853","ts":1789343018765,"field":"cvss","old":"7.5","new":null},{"seq":176453,"id":"CVE-2026-56853","ts":1789343018765,"field":"severity","old":"high","new":"none"},{"seq":174571,"id":"CVE-2026-56853","ts":1789334771605,"field":"cvss","old":null,"new":"7.5"},{"seq":174570,"id":"CVE-2026-56853","ts":1789334771605,"field":"severity","old":"none","new":"high"},{"seq":173366,"id":"CVE-2026-56853","ts":1789333512057,"field":"cvss","old":"7.5","new":null},{"seq":173365,"id":"CVE-2026-56853","ts":1789333512057,"field":"severity","old":"high","new":"none"},{"seq":172180,"id":"CVE-2026-56853","ts":1789331018036,"field":"cvss","old":null,"new":"7.5"},{"seq":172179,"id":"CVE-2026-56853","ts":1789331018036,"field":"severity","old":"none","new":"high"},{"seq":170994,"id":"CVE-2026-56853","ts":1789328614576,"field":"cvss","old":"7.5","new":null},{"seq":170993,"id":"CVE-2026-56853","ts":1789328614576,"field":"severity","old":"high","new":"none"},{"seq":169789,"id":"CVE-2026-56853","ts":1789327050983,"field":"cvss","old":null,"new":"7.5"},{"seq":169788,"id":"CVE-2026-56853"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