# CVE-2023-32732: Denial-of-Service in gRPC > A malicious client can cause a denial of service by sending malformed base64 headers, disconnecting the gRPC server from HTTP2 proxies. - **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 9 Jun 2023 - **Updated:** 13 Feb 2025 - **Also known as:** BELL-CVE-2023-32732, DEBIAN-CVE-2023-32732, GHSA-9hxf-ppjv-w6rq, PYSEC-2026-1426, UBUNTU-CVE-2023-32732 ## What is CVE-2023-32732? CVE-2023-32732 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 9 Jun 2023. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description gRPC contains a vulnerability whereby a client can cause a termination of connection between a HTTP2 proxy and a gRPC server: a base64 encoding error for `-bin` suffixed headers will result in a disconnection by the gRPC server, but is typically allowed by HTTP2 proxies. We recommend upgrading beyond the commit in  https://github.com/grpc/grpc/pull/32309 https://www.google.com/url Weakness: CWE-440 (Expected Behavior Violation) ## Which versions are affected by CVE-2023-32732? 13 open source packages ship an affected version, including grpcio, io.grpc:grpc-protobuf and grpc. It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `grpcio` | PyPI | From 1.53.0 | 1.53.1, 1.54.2 | | `grpcio` | PyPI | From 1.53.0 | 1.53.1 | | `grpcio` | PyPI | From 1.53.0 | 1.53.1 | | `grpcio` | PyPI | From 1.54.0 | 1.54.2 | | `grpcio` | PyPI | From 1.54.0 | 1.54.2 | | `io.grpc:grpc-protobuf` | Maven | From 1.53.0 | 1.53.1 | | `io.grpc:grpc-protobuf` | Maven | From 1.53.0 | 1.53.1 | | `io.grpc:grpc-protobuf` | Maven | From 1.54.0 | 1.54.2 | | `io.grpc:grpc-protobuf` | Maven | From 1.54.0 | 1.54.2 | | `grpc` | RubyGems | From 1.53.0 | 1.53.1 | | `grpc` | RubyGems | From 1.53.0 | 1.53.1 | | `grpc` | RubyGems | From 1.54.0 | 1.54.2 | | `grpc` | RubyGems | From 1.54.0 | 1.54.2 | Products: Fedoraproject Fedora, Grpc Grpc. ## How do I fix CVE-2023-32732? Upgrade grpcio to a fixed version for your release line: 1.53.1 or 1.54.2. ## Is CVE-2023-32732 being exploited? There is no known exploitation of CVE-2023-32732 in the wild and no public exploit code. ## Other vulnerabilities in Fedoraproject Fedora - [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild) - [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild) - [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-32732 and fix it if it is affected. What it is: CVE-2023-32732 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 9 Jun 2023. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2023-32732 in the wild and no public exploit code. Affected packages and fixed versions: - grpcio (PyPI): affected from 1.53.0; fixed in 1.53.1, 1.54.2 - grpcio (PyPI): affected from 1.53.0; fixed in 1.53.1 - grpcio (PyPI): affected from 1.53.0; fixed in 1.53.1 - grpcio (PyPI): affected from 1.54.0; fixed in 1.54.2 - grpcio (PyPI): affected from 1.54.0; fixed in 1.54.2 - io.grpc:grpc-protobuf (Maven): affected from 1.53.0; fixed in 1.53.1 - io.grpc:grpc-protobuf (Maven): affected from 1.53.0; fixed in 1.53.1 - io.grpc:grpc-protobuf (Maven): affected from 1.54.0; fixed in 1.54.2 - io.grpc:grpc-protobuf (Maven): affected from 1.54.0; fixed in 1.54.2 - grpc (RubyGems): affected from 1.53.0; fixed in 1.53.1 - grpc (RubyGems): affected from 1.53.0; fixed in 1.53.1 - grpc (RubyGems): affected from 1.54.0; fixed in 1.54.2 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/CVE-2023-32732/ (Markdown: https://insights.sbomify.com/CVE-2023-32732/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-32732 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-32732 - OSV: https://osv.dev/vulnerability/CVE-2023-32732 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-32732/ Summaries are generated and may contain mistakes; the official description above is the record.