---
id: "CVE-2026-84445"
kind: "vulnerability"
aliases: ["CVE-2026-84445", "GHSA-2v4p-qf9q-27wj", "GO-2026-6443"]
title: "Server panic via missing authority or Host headers in google.golang.org/grpc"
severity: "high"
cvss: 8.7
epss: 0.00641
exploited: false
status: "open"
category: "package"
products: [{"name": "google.golang.org/grpc", "fixed": ["1.82.2", "1.83.2", "1.84.0-dev.0.20260825144003-d5a41119e0e3", "1.85.0-dev.0.20260825072537-93e31b48545e"], "affected": ">= 1.85.0-dev, < 1.85.0-dev.0.20260825072537-93e31b48545e", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["go", "grpc-go", "package", "xds-server"]
not_affected_if: ["grpc-version-fixed", "no-xds-server"]
published_at: "2026-09-14T17:17:51+00:00"
first_seen_at: "2026-10-23T19:13:08+00:00"
updated_at: "2026-10-23T21:44:07+00:00"
sources: [{"source": "govuln", "url": "https://pkg.go.dev/vuln/GO-2026-6443", "first_seen_at": "2026-10-23T19:13:08+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-84445", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-84445", "first_seen_at": "2026-10-23T19:35:23+00:00"}]
---

# Server panic via missing authority or Host headers in google.golang.org/grpc

gRPC-Go servers created with xds.NewGRPCServer() can be crashed by an RPC that carries neither an :authority nor a Host header, because the routing code indexes an empty slice. A remote client that can establish a transport connection can take down the entire server process.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:google.golang.org/grpc affected >= 1.85.0-dev, < 1.85.0-dev.0.20260825072537-93e31b48545e fixed 1.82.2, 1.83.2, 1.84.0-dev.0.20260825144003-d5a41119e0e3, 1.85.0-dev.0.20260825072537-93e31b48545e

## How to check

Search the codebase for xds.NewGRPCServer() and check google.golang.org/grpc in go.mod or go.sum for a version below 1.82.2 or 1.83.2.

## Fix

Upgrade google.golang.org/grpc to 1.82.2 or 1.83.2 (or a later release that includes the fix).

## Timeline

- 2026-10-23T19:13:08+00:00 govuln https://pkg.go.dev/vuln/GO-2026-6443
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-84445
- 2026-10-23T19:35:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-84445

## From the sources

gRPC-Go is the Go language implementation of gRPC. Prior to 1.82.2 and 1.83.2, servers created with xds.NewGRPCServer() allow internal/transport/http2_server.go to accept an RPC containing neither the :authority header nor the Host header, while RouteAndProcess in internal/xds/server/routing.go assumes that an authority value exists and indexes the empty slice. A remote client that can complete transport connection establishment can trigger an index-out-of-bounds panic that is not recovered by the per-RPC goroutine and terminates the entire server process. In insecure or ordinary TLS deployments the request can be unauthenticated, while strict mTLS or ALTS deployments require valid transport credentials before the malformed RPC can reach the interceptor. This issue is fixed in versions 1.82.2 and 1.83.2.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_