This PR contains the following updates:
gRPC-Go xDS servers: Denial of Service (DoS) via crash due to missing :authority and Host headers
CVE-2026-84445 / GHSA-2v4p-qf9q-27wj
More information
Details
A vulnerability exists in gRPC-Go servers configured with xds.NewGRPCServer() where a crafted request missing both :authority and Host headers can cause a server panic, resulting in a Denial of Service (DoS).
Servers built with xds.NewGRPCServer install an xDS routing interceptor on every RPC. This interceptor looks up the request’s :authority header to pick a virtual host. The HTTP/2 server transport previously accepted requests that had neither :authority nor Host. When this happened, the xDS routing interceptor attempted to access the first element of an empty slice of authorities, leading to an index out of bounds panic. Since the per-RPC goroutine does not recover from panics, the entire server process would terminate.
This panic occurs in the interceptor pipeline, meaning the transport credentials handshake (TLS, mTLS, or ALTS) and HTTP/2 connection establishment must complete successfully before the crafted request can reach this logic.
- Insecure/Standard TLS: If the server permits insecure (plaintext) connections or standard credentials (where client certs are not checked), any unauthenticated remote attacker can trigger the crash.
- mTLS / ALTS: If strict transport-level authentication is enforced at the network edge or transport layer (e.g., requiring a valid client certificate), the attacker must possess valid transport credentials to initiate the stream and trigger the panic.
Impact
An attacker can cause a complete outage of the gRPC server by sending a request missing both :authority and Host headers, provided they can successfully establish a transport connection.
Patches
The issue has been addressed in master (and backported to 1.83.2 and 1.82.2). The fix updates the HTTP/2 transport layer to reject requests missing both :authority and Host headers early, maintaining consistency with and other gRPC language implementations.
Severity
High
References
This data is provided by the GitHub Advisory Database (CC-BY 4.0).
Release Notes
grpc/grpc-go (google.golang.org/grpc)
v1.83.2: Release 1.83.2
Compare Source
Security
- server: Reject requests missing both
:authority and Host headers with HTTP 400 and status Internal. (#9365)
Configuration
📅 Schedule: (UTC)
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- At any time (no schedule defined)
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- At any time (no schedule defined)
🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.
♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.
🔕 Ignore: Close this PR and you won't be reminded about this update again.
This PR was generated by Mend Renovate. View the repository job log.
This PR contains the following updates:
v1.83.1→v1.83.2gRPC-Go xDS servers: Denial of Service (DoS) via crash due to missing
:authorityandHostheadersCVE-2026-84445 / GHSA-2v4p-qf9q-27wj
More information
Details
A vulnerability exists in gRPC-Go servers configured with
xds.NewGRPCServer()where a crafted request missing both:authorityandHostheaders can cause a server panic, resulting in a Denial of Service (DoS).Servers built with
xds.NewGRPCServerinstall an xDS routing interceptor on every RPC. This interceptor looks up the request’s:authorityheader to pick a virtual host. The HTTP/2 server transport previously accepted requests that had neither:authoritynorHost. When this happened, the xDS routing interceptor attempted to access the first element of an empty slice of authorities, leading to an index out of bounds panic. Since the per-RPC goroutine does not recover from panics, the entire server process would terminate.This panic occurs in the interceptor pipeline, meaning the transport credentials handshake (TLS, mTLS, or ALTS) and HTTP/2 connection establishment must complete successfully before the crafted request can reach this logic.
Impact
An attacker can cause a complete outage of the gRPC server by sending a request missing both
:authorityandHostheaders, provided they can successfully establish a transport connection.Patches
The issue has been addressed in
master(and backported to1.83.2and1.82.2). The fix updates the HTTP/2 transport layer to reject requests missing both:authorityandHostheaders early, maintaining consistency with and other gRPC language implementations.Severity
High
References
This data is provided by the GitHub Advisory Database (CC-BY 4.0).
Release Notes
grpc/grpc-go (google.golang.org/grpc)
v1.83.2: Release 1.83.2Compare Source
Security
:authorityandHostheaders with HTTP 400 and statusInternal. (#9365)Configuration
📅 Schedule: (UTC)
🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.
♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.
🔕 Ignore: Close this PR and you won't be reminded about this update again.
This PR was generated by Mend Renovate. View the repository job log.