CVE-2022-2880 in Google
Summary
by MITRE • 10/14/2022
Requests forwarded by ReverseProxy include the raw query parameters from the inbound request, including unparseable parameters rejected by net/http. This could permit query parameter smuggling when a Go proxy forwards a parameter with an unparseable value. After fix, ReverseProxy sanitizes the query parameters in the forwarded query when the outbound request's Form field is set after the ReverseProxy. Director function returns, indicating that the proxy has parsed the query parameters. Proxies which do not parse query parameters continue to forward the original query parameters unchanged.
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Analysis
by VulDB Data Team • 05/28/2026
The vulnerability identified as CVE-2022-2880 represents a significant security flaw in Go's ReverseProxy implementation that enables query parameter smuggling attacks. This issue arises from the improper handling of query parameters during HTTP request forwarding operations. When a reverse proxy processes incoming requests, it forwards query parameters from the original request to downstream servers without adequate sanitization. The vulnerability specifically manifests when the net/http package encounters unparseable query parameters that are rejected during parsing, yet these malformed parameters are still forwarded through the proxy chain.
The technical flaw stems from the inconsistent behavior between different proxy implementations and the Go standard library's HTTP handling mechanisms. In the affected scenario, when a ReverseProxy receives an HTTP request containing malformed query parameters, the net/http package's parsing logic rejects these unparseable parameters but the proxy continues to forward the raw query string unchanged. This creates an opportunity for attackers to exploit the difference between how the proxy handles parameters versus how downstream servers interpret them. The vulnerability is particularly dangerous because it leverages the natural parsing behavior of Go's HTTP libraries to create a discrepancy in parameter handling that can be exploited for malicious purposes.
The operational impact of this vulnerability extends beyond simple parameter forwarding issues to encompass potential security breaches through query parameter smuggling techniques. Attackers can craft requests with specifically formatted query parameters that appear valid to the proxy server but contain malicious content that downstream applications interpret differently. This creates a vector for various attacks including but not limited to cache poisoning, cross-site scripting exploitation, and command injection attempts. The vulnerability particularly affects systems where the proxy server and backend applications have different interpretations of query parameter syntax, creating a window for attackers to inject malicious content that bypasses normal security controls.
The fix implemented for CVE-2022-2880 addresses this vulnerability by introducing proper query parameter sanitization within the ReverseProxy mechanism. When the outbound request's Form field is set after the ReverseProxy Director function returns, the proxy now properly sanitizes query parameters to ensure consistency between the proxy's handling and the downstream server's interpretation. This mitigation aligns with established security practices and follows the principle of least privilege by ensuring that only properly parsed and validated parameters are forwarded. The solution specifically targets the scenario where proxies parse query parameters and ensures that any previously unparseable parameters are properly handled before forwarding. This approach addresses the underlying CWE-1177 vulnerability category related to improper handling of input data and aligns with ATT&CK technique T1071.004 for application layer protocol manipulation.
Organizations implementing Go-based reverse proxies must carefully evaluate their current configurations to ensure proper parameter handling and consider upgrading to versions that include the CVE-2022-2880 fix. The vulnerability demonstrates the importance of consistent input validation across all layers of an application architecture and highlights the potential for subtle implementation differences to create security vulnerabilities. Security teams should implement monitoring for unusual query parameter patterns that might indicate exploitation attempts and ensure that all proxy configurations follow the updated sanitization practices. The mitigation strategy emphasizes the need for comprehensive testing of proxy configurations to verify that parameter handling behaves consistently across different components of the system architecture.