GHSA-cfgp-2977-2fmm
HIGHConnection confusion in gRPC
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.
Blast Radius
io.grpc:grpc-protobuf☕io.grpc:grpc-protobuf🐍grpcio🐍grpcio💎grpc💎grpcReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven, PyPI packages — download data is not available via public APIs for these ecosystems.
Description
When gRPC HTTP2 stack raised a header size exceeded error, it skipped parsing the rest of the HPACK frame. This caused any HPACK table mutations to also be skipped, resulting in a desynchronization of HPACK tables between sender and receiver. If leveraged, say, between a proxy and a backend, this could lead to requests from the proxy being interpreted as containing headers from different proxy clients - leading to an information leak that can be used for privilege escalation or data exfiltration.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.grpc:grpc-protobuf | ≥ 1.53.0&&< 1.53.1 | 1.53.1 |
| ☕Maven | io.grpc:grpc-protobuf | ≥ 1.54.0&&< 1.54.2 | 1.54.2 |
| 🐍PyPI | grpcio | ≥ 1.53.0&&< 1.53.1 | 1.53.1 |
| 🐍PyPI | grpcio | ≥ 1.54.0&&< 1.54.2 | 1.54.2 |
| 💎RubyGems | grpc | ≥ 1.53.0&&< 1.53.1 | 1.53.1 |
| 💎RubyGems | grpc | ≥ 1.54.0&&< 1.54.2 | 1.54.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.grpc:grpc-protobuf. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update io.grpc:grpc-protobuf to 1.53.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cfgp-2977-2fmm 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 pinpoints whether GHSA-cfgp-2977-2fmm is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-cfgp-2977-2fmm. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-cfgp-2977-2fmm in your dependencies?
O3 detects GHSA-cfgp-2977-2fmm across Maven, PyPI, RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.