CVE-2023-32731: Connection confusion in gRPC
Summary
CVE-2023-32731: Connection confusion in gRPC. Affects Grpc.Core versions < 2.52.0. Fixed in 2.52.0. How to fix ↓
Also tracked for
- grpcio · PyPI
- io.grpc:grpc-protobuf · Maven
The same CVE-2023-32731 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
The gRPC package is a high-performance, open-source framework developed by Google for building distributed systems. It provides a powerful and efficient way to connect and communicate between services using remote procedure calls (RPCs). gRPC supports multiple programming languages and is widely used in various applications and platforms.
Vulnerability Detail
The vulnerability in gRPC arises from a connection confusion issue within the HTTP2 stack. When the stack encounters a header size exceeded error, it stops parsing the rest of the HPACK frame. This behavior leads to a desynchronization of HPACK tables between the sender and receiver, particularly when used between a proxy and a backend. An attacker can leverage this vulnerability to cause requests from the proxy to be interpreted as containing headers from different proxy clients. This can result in an information leak that may be exploited for privilege escalation or data exfiltration.
How To Fix
Latest published version: 2.46.6 as of 23 Oct 2026
Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
2.52.0
This is the first release that contains the fix.
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Workaround
There is no specific workaround mentioned for this vulnerability.
Conclusion
The gRPC package is susceptible to a connection confusion vulnerability that can result in an information leak. It is crucial to upgrade to a fixed version of gRPC (2.52.0 or above) to mitigate the risk. For further support and assistance in vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for Grpc.Core →
FAQ
gRPC is an open-source framework developed by Google for building distributed systems using remote procedure calls (RPCs). It provides high-performance and efficient communication between services.
The vulnerability can lead to an information leak, allowing an attacker to escalate privileges or exfiltrate data by manipulating headers in requests.
To fix this vulnerability, you should upgrade to a version of gRPC that includes the necessary fix. Specifically, versions 2.52.0 and above contain the fix.
No specific workarounds have been provided for this vulnerability.
You can find more information about this vulnerability in the GitHub advisory database: [link to the advisory]
References
Related vulnerabilities
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