# CVE-2026-84445: gRPC-Go xDS server denial of service via missing headers

Source: https://junglewise.ai/threats/cve-2026-84445-grpc-go-xds-server-denial-of-service-via-missing-headers  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-14. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-84445 · Severity: high · CVSS 4 · Published 2026-09-14

gRPC-Go is a popular RPC framework used to build distributed applications and microservices. When configured with xDS routing (a service mesh feature), servers crash if they receive HTTP/2 requests missing both the `:authority` and `Host` headers, causing a complete service outage. An attacker who can establish a network connection to the server can trigger this crash remotely.

Technologies: [google.golang.org/grpc (Go)](https://junglewise.ai/threats/technologies/google-golang-org-grpc). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-84445 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-84445 being exploited in the wild.

**How severe is CVE-2026-84445?** High severity, with a CVSS score of 4, published 14 September 2026.

**Which products and versions are affected?** google.golang.org/grpc (Go) SEMVER:introduced=0,fixed=1.82.2, SEMVER:introduced=0,fixed=1.82.2,introduced=1.83.0,fixed=1.83.2,introduced=1.84.0-dev,fixed=1.85.0-dev.0.20260825072537-93e31b48545e.

**Is there a fix for CVE-2026-84445?** Yes. google.golang.org/grpc (Go): upgrade to 1.82.2, 1.85.0-dev.0.20260825072537-93e31b48545e or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-84445 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-84445?** Check whether you run google.golang.org/grpc (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- google.golang.org/grpc (Go): upgrade to 1.82.2, 1.85.0-dev.0.20260825072537-93e31b48545e or later

  ```sh
  go get google.golang.org/grpc@v1.85.0-dev.0.20260825072537-93e31b48545e
  ```


## Technical details

This vulnerability is an uncaught exception (CWE-248) combined with improper array index validation (CWE-129). The root cause lies in the HTTP/2 transport layer which previously accepted requests missing both the `:authority` and `Host` headers. When such a request reaches the xDS routing interceptor, it attempts to look up the request's `:authority` header in an empty slice of authorities, causing an index out of bounds panic. Since the per-RPC goroutine lacks panic recovery, the entire server process terminates. The attack requires successful completion of the transport credentials handshake (TLS/mTLS/ALTS) and HTTP/2 connection establishment before the malicious request can reach the interceptor. On insecure or standard TLS connections, unauthenticated remote attackers can trigger the crash; on mTLS/ALTS, valid transport credentials are required. Patches are available in versions 1.82.2, 1.83.2, and 1.85.0-dev.0.20260825072537-93e31b48545e, which enforce early rejection of requests missing both headers.

## Affected products

- Google gRPC-Go < 1.82.2; 1.83.0 - 1.83.1; 1.84.0-dev - < 1.85.0-dev.0.20260825072537-93e31b48545e

## Identifiers

- CVE-2026-84445
- GHSA-2v4p-qf9q-27wj
- GO-2026-6443

## Timeline

- 2026-08-25: disclosed
- 2026-08-25: patched: Patches released for versions 1.82.2, 1.83.2, and 1.85.0-dev branch
- 2026-09-08: advisory

## References

- [https://api.github.com/users/matiasinsaurralde](https://api.github.com/users/matiasinsaurralde)
- [https://github.com/matiasinsaurralde](https://github.com/matiasinsaurralde)
- [https://api.github.com/users/matiasinsaurralde/gists%7B/gist_id%7D](https://api.github.com/users/matiasinsaurralde/gists%7B/gist_id%7D)
- [https://api.github.com/users/matiasinsaurralde/repos](https://api.github.com/users/matiasinsaurralde/repos)
- [https://avatars.githubusercontent.com/u/20110?v=4](https://avatars.githubusercontent.com/u/20110?v=4)
- [https://api.github.com/users/matiasinsaurralde/events%7B/privacy%7D](https://api.github.com/users/matiasinsaurralde/events%7B/privacy%7D)

## Related threats

- [gRPC-Go heap memory exhaustion via HTTP/2 DATA frame fragmentation](https://junglewise.ai/threats/cve-2026-84304-grpc-go-heap-memory-exhaustion-via-http-2-data-frame)
- [gRPC-Go xDS RBAC HTTP filter bypass via case-sensitive header matching](https://junglewise.ai/threats/cve-2026-84303-grpc-go-xds-rbac-http-filter-bypass-via-case-sensitive-header)
- [GO-2026-6061 - Vulnerabilities in the xDS RBAC authorization engine and the HTTP/2 transport server implementation in…](https://junglewise.ai/threats/go-2026-6061-vulnerabilities-in-the-xds-rbac-authorization-engine-and-2c07d92a)
- [gRPC-Go auth bypass and DoS in xDS RBAC and HTTP/2 transport](https://junglewise.ai/threats/grpc-go-auth-bypass-and-dos-in-xds-rbac-and-http-2-transport-878951d5)
- [gRPC gRPC-Go authorization bypass in HTTP/2 path validation](https://junglewise.ai/threats/cve-2026-33186-grpc-grpc-go-authorization-bypass-in-http-2-path-validation)