CVE-2023-4785 is a high-severity (CVSS 7.5) CWE-248 vulnerability in grpcio. A fix is available for grpcio — see the affected versions and patch details below.
Denial of Service in gRPC Core
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-4785.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-4785 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
grpcio🐍grpcio🐍grpcio💎grpc💎grpc💎grpc💎grpcReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Lack of error handling in the TCP server in Google's gRPC starting version 1.23 on posix-compatible platforms (ex. Linux) allows an attacker to cause a denial of service by initiating a significant number of connections with the server. Note that gRPC C++ Python, and Ruby are affected, but gRPC Java, and Go are NOT affected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | grpcio | ≥ 1.55.0&&< 1.55.3 | 1.55.3pip install --upgrade 'grpcio==1.55.3' |
| 🐍PyPI | grpcio | ≥ 1.54.0&&< 1.54.3 | 1.54.3pip install --upgrade 'grpcio==1.54.3' |
| 🐍PyPI | grpcio | ≥ 1.53.0&&< 1.53.2 | 1.53.2pip install --upgrade 'grpcio==1.53.2' |
| 💎RubyGems | grpc | ≥ 1.56.0&&< 1.56.2 | 1.56.2bundle update grpc --conservative |
| 💎RubyGems | grpc | ≥ 1.55.0&&< 1.55.3 | 1.55.3bundle update grpc --conservative |
| 💎RubyGems | grpc | ≥ 1.54.0&&< 1.54.3 | 1.54.3bundle update grpc --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for grpcio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update grpcio to 1.55.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-4785 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-4785 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-4785. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Satellite 6.14 for RHEL 8 | rubygem-grpc-0:1.58.0-1.el8sat | RHSA-2024:0797 |
Frequently Asked Questions
Is CVE-2023-4785 in your dependencies?
O3 Security finds CVE-2023-4785 across PyPI, RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.