GO · SEPTEMBER 2026 · EARLY WARNING

gRPC-Go xDS Servers: DoS Vulnerability via Missing Headers

EARLY WARNING · UNCONFIRMED. This page describes a developing threat that 0Day surfaced from early signals and has not yet independently confirmed. Details may change. Always verify against the primary sources before acting.
Severity
HIGH
Affected component
grpc-go (go)
Patched version
Not yet available
GHSA-2V4P-QF9Q-27WJ

An early warning has been issued regarding a high-severity vulnerability in gRPC-Go servers configured with `xds.NewGRPCServer()`. This vulnerability can lead to a server panic and Denial of Service (DoS) when a crafted request missing both `:authority` and `Host` headers is received.

What happened

An early warning has been issued for a critical vulnerability in gRPC-Go servers that use the `xds.NewGRPCServer()` configuration. This vulnerability can cause a server to panic and result in a Denial of Service (DoS) condition when it receives a specially crafted request that lacks both the `:authority` and `Host` headers. The issue was first flagged on 2026-09-08 and is currently under investigation. No exploitation in the wild has been confirmed at this time.

The vulnerability affects the `grpc-go` component in Go applications. However, an authoritative version range has not been published yet. Users of gRPC-Go are advised to stay informed about updates from the primary sources.

What to do about it

How 0Day would have caught this

MATCHED TO YOUR ACTUAL DEPENDENCY GRAPH0Day matches every incoming threat signal against your GitHub organization’s full dependency graph, including transitive dependencies. If grpc-go is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.

Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.

Frequently asked questions

Am I affected?

If your application uses gRPC-Go servers configured with `xds.NewGRPCServer()`, you may be affected. However, an authoritative version range has not been published yet. Consult the primary sources for the most current information.

What should I do right now?

Monitor the primary sources for updates and consider upgrading to a version of gRPC-Go that includes the fix, such as `1.83.2` or `1.82.2`, if available. Review your application's configuration and implement additional input validation.

Has an official fix been released?

No official fix has been published yet. Monitor the primary sources for updates on any released patches.

Sources

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