# GHSA-hrxh-6v49-42gf: gRPC-Go: xDS RBAC and HTTP/2 Vulnerabilities > Attackers can bypass gRPC authorization or cause denial of service via HTTP/2 stream floods in Go applications using xDS RBAC. - **Severity:** Not scored - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 21 Jul 2026 - **Also known as:** GO-2026-6061 ## What is GHSA-hrxh-6v49-42gf? GHSA-hrxh-6v49-42gf is an authentication bypass vulnerability in google.golang.org/grpc, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Multiple security vulnerabilities have been identified and addressed in grpc-go affecting the xDS RBAC authorization engine (internal/xds/rbac) and the HTTP/2 transport server implementation (internal/transport). These vulnerabilities could result in: - Authorization Bypass (Fail-Open) when translating xDS RBAC policies containing `Metadata` or `RequestedServerName` fields. - Denial of Service (High CPU Consumption) due to an HTTP/2 Rapid Reset mitigation bypass during client-initiated stream resets. - Denial of Service (Server Panic) when parsing crafted xDS RBAC policies containing `NOT` rules around unsupported fields. ### Impact _What kind of vulnerability is it? Who is impacted?_ #### xDS RBAC Authorization Bypass via `Metadata` & `RequestedServerName` matchers - Affected Component: xDS RBAC - Impact: When building policy matchers for gRPC RBAC from xDS configurations, unsupported `permission` and `principal` rules (specifically `Metadata` and `RequestedServerName`) were silently ignored and treated as no-ops. - If an authorization policy relied purely on these matchers for access control, treating those rules as no-ops effectively removed the restrictions. - If these unsupported rules were nested inside logical `NOT` rules (`Permission_NotRule` / `Principal_NotId`) or multi-condition `OR/AND` rules, silently dropping them changed the boolean logic flow of the authorization engine. As a result, policy evaluation decisions could fail open, allowing unauthorized clients to access protected gRPC services or resources. #### HTTP/2 Rapid Reset Mitigation Bypass / Denial of Service via Stream Aborts - Affected Component: HTTP/2 transport - Impact: Earlier mitigations in grpc-go for HTTP/2 Rapid Reset only applied threshold checks to items that directly resulted in control frames being written back to the wire, such as `SETTINGS` ACKs or server-initiated `RST_STREAM`s. When a client initiated a rapid flood of stream creation (`HEADERS`) immediately followed by stream termination `RST_STREAM`, items queued up in the control buffer without counting against the transport response frame threshold. An attacker can repeatedly trigger this flood sequence to bypass reader blocking, resulting in high CPU usage, and Denial of Service (DoS). #### Denial of Service (Panic) in xDS RBAC Engine via Unsupported Fields inside NOT Rules - Affected Component: xDS RBAC - Impact: The xDS RBAC policy translators recursively generate matchers for nested rules. When a `NOT` rule wrapped an unsupported or unhandled field (such as `SourcedMetadata`), the recursive step returned an empty matcher. This could result in a runtime panic when the RBAC engine attempts to authorize an incoming request. An attacker or misconfigured/malicious xDS management server delivering an LDS/RDS update containing a `NOT` rule around an unhandled field causes the gRPC server process to crash immediately (CWE-248 / Denial of Service). ### Patches _Has the problem been patched? What versions should users upgrade to?_ All three issues have been fixed in `master` and will be released in 1.82.1 shortly. ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ If upgrading grpc-go immediately is not possible, apply the following workarounds based on your deployment architecture: * For xDS RBAC Vulnerabilities & Panics: Ensure that upstream xDS management servers do not push RBAC policies containing `Metadata`, `RequestedServerName`, or `NOT` rules wrapping unsupported fields (such as `SourcedMetadata`) to grpc-go servers. * For HTTP/2 Rapid Reset DOS: Configure upstream reverse proxies or load balancers (such as Envoy) with strict HTTP/2 `max_concurrent_streams` limits and active rate limiting on `RST_STREAM` frequency per connection. ### Severity | Vulnerability | Qualitative Severity | Approximate CVSS v3.1 Score | Primary Impact | | :--- | :--- | :--- | :--- | | **xDS RBAC Authorization Bypass** | **High** | `8.2` | Unauthorized Access / Fail-Open | | **HTTP/2 Rapid Reset DOS Bypass** | **High** | `7.5` | High CPU Consumption / Denial of Service | | **xDS RBAC Engine Server Panic** | **Medium** | `5.9` | Process Crash / Denial of Service | ## Which versions are affected by GHSA-hrxh-6v49-42gf? 3 open source packages ship an affected version, including google.golang.org/grpc. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `google.golang.org/grpc` | Go | All versions | 1.82.1 | | `google.golang.org/grpc` | Go | All versions | 1.82.1 | | `google.golang.org/grpc` | Go | All versions | 1.82.1 | ## How do I fix GHSA-hrxh-6v49-42gf? Upgrade google.golang.org/grpc to 1.82.1 or later. ## Is GHSA-hrxh-6v49-42gf being exploited? There is no known exploitation of GHSA-hrxh-6v49-42gf in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for GHSA-hrxh-6v49-42gf and fix it if it is affected. What it is: GHSA-hrxh-6v49-42gf is an authentication bypass vulnerability in google.golang.org/grpc, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of GHSA-hrxh-6v49-42gf in the wild and no public exploit code. Affected packages and fixed versions: - google.golang.org/grpc (Go): affected all versions; fixed in 1.82.1 - google.golang.org/grpc (Go): affected all versions; fixed in 1.82.1 - google.golang.org/grpc (Go): affected all versions; fixed in 1.82.1 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/GHSA-hrxh-6v49-42gf/ (Markdown: https://insights.sbomify.com/GHSA-hrxh-6v49-42gf/index.md) ``` ## Sources - OSV: https://osv.dev/vulnerability/GHSA-hrxh-6v49-42gf --- From sbomify Insights: https://insights.sbomify.com/GHSA-hrxh-6v49-42gf/ Summaries are generated and may contain mistakes; the official description above is the record.