GHSA-cfgp-2977-2fmm is a high-severity (CVSS 7.4) CWE-440 vulnerability in io.grpc:grpc-protobuf. A fix is available for io.grpc:grpc-protobuf — see the affected versions and patch details below.
Connection confusion in gRPC
Exploitation Status
No confirmed exploitation observed yet
- 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 GHSA-cfgp-2977-2fmm.
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
GHSA-cfgp-2977-2fmm 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 377,238 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
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 | 1.53.1io.grpc:grpc-protobuf:1.53.1 |
| ☕Maven | io.grpc:grpc-protobuf | ≥ 1.54.0&&< 1.54.2 | 1.54.2io.grpc:grpc-protobuf:1.54.2 |
| 🐍PyPI | grpcio | ≥ 1.53.0&&< 1.53.1 | 1.53.1pip install --upgrade 'grpcio==1.53.1' |
| 🐍PyPI | grpcio | ≥ 1.54.0&&< 1.54.2 | 1.54.2pip install --upgrade 'grpcio==1.54.2' |
| 💎RubyGems | grpc | ≥ 1.53.0&&< 1.53.1 | 1.53.1bundle update grpc --conservative |
| 💎RubyGems | grpc | ≥ 1.54.0&&< 1.54.2 | 1.54.2bundle 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 io.grpc:grpc-protobuf, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-cfgp-2977-2fmm can be triaged on real exposure rather than presence alone.
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.
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 Enterprise Linux 9 | rhc-worker-playbook-0:0.1.10-1.el9_5 | RHSA-2024:10761 |
Frequently Asked Questions
Is GHSA-cfgp-2977-2fmm in your dependencies?
O3 Security finds GHSA-cfgp-2977-2fmm across Maven, PyPI, RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.