High [CVE-2026-56853] Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial of Service
This high-severity Red Hat Linux advisory covers CVE-2026-56853 affecting Assisted Installer for Red Hat OpenShift Container Platform 2, AWS Load Balancer Operator, Builds for Red Hat OpenShift.
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Summary
A flaw was found in the `net/http` component of the Go standard library. When a server is configured to support unencrypted HTTP/2, it reads initial bytes from new connections to detect the HTTP/2 client preface.
However, the `ReadHeaderTimeout` is not correctly applied during this process. This oversight could allow a remote attacker to maintain open connections indefinitely, potentially leading to a Denial of Service (DoS) by exhausting server resources.
Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-770.
Affected products named by the advisory: Assisted Installer for Red Hat OpenShift Container Platform 2; AWS Load Balancer Operator; Builds for Red Hat OpenShift; cert-manager Operator for Red Hat OpenShift; and 53 more.
Affected products named by the advisory: Compliance Operator; Confidential Compute Attestation; Cryostat 4; Custom Metric Autoscaler operator for Red Hat Openshift; and 49 more.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
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