Overview
CVE-2026-35548 describes a logic flaw in guardsix (formerly Logpoint) ODBC Enrichment Plugins where stored database credentials could be reused after the target Host, IP address, or Port were modified. An authenticated Operator could redirect the database connection to unintended internal systems, enabling SSRF and potential misuse of valid stored credentials. In real-world Go (Gin) services, SSRF-like behavior can occur when an application uses client-supplied destinations to fetch resources or to connect to internal services without strict validation or credential revalidation, leading to exposure or misuse of internal resources and credentials stored for those destinations. This guide anchors remediation against the CVE's lesson-do not reuse credentials or cached connection details when an endpoint changes, and ensure outbound requests are constrained to trusted destinations.
In a Go (Gin) context, SSRF typically occurs when an endpoint handler accepts a URL or destination from a client and uses it to fetch data or reach another service. If the code caches or reuses connection data (like a previously established HTTP client, credentials, or a stored destination) when the target changes, an attacker can redirect requests to internal systems or exfiltrate data, similar to the guardsix vulnerability pattern. The CVE highlights the risk of allowing endpoint changes to bypass existing credential usage, which in Go code translates to reusing a cached or pre-approved destination and credentials after the target is modified.
Remediation focuses on (a) validating and strictly whitelisting destinations, (b) disallowing or tightly controlling redirects, (c) using per-request credentials and strict timeouts, and (d) avoiding reuse of stored credentials when a target changes. In Go with Gin, this means never feeding a user-supplied URL directly into outbound requests, implementing an allowlist of destinations, resolving hosts safely, and rotating or tying credentials to a per-target context. Automated tests should cover changes to endpoints to ensure credentials are not unintentionally reused and that SSRF paths are blocked by design.
Affected Versions
GuardSix ODBC Enrichment Plugins: vulnerable before 5.2.1; 5.2.1 is used in guardsix 7.9.0.0.
Code Fix Example
Go (Gin) API Security Remediation
package main
import (
"crypto/tls"
"errors"
"io"
"net"
"net/http"
"net/url"
"time"
"github.com/gin-gonic/gin"
)
// Simple allowlist for demonstration. In production, populate from config.
var allowlist = map[string]bool{
"example.com": true,
"api.example.org": true,
}
func isPrivateIP(ip net.IP) bool {
if ip == nil {
return true
}
if ip.IsLoopback() || ip.IsUnspecified() {
return true
}
if ip4 := ip.To4(); ip4 != nil {
switch {
case ip4[0] == 10:
return true
case ip4[0] == 172 && ip4[1] >= 16 && ip4[1] <= 31:
return true
case ip4[0] == 192 && ip4[1] == 168:
return true
}
}
return false
}
func isAllowedTarget(target string) bool {
u, err := url.Parse(target)
if err != nil {
return false
}
host := u.Hostname()
if host == "" {
return false
}
// Restrict to public hosts listed in allowlist
if ip := net.ParseIP(host); ip != nil {
// Do not allow raw IPs unless explicitly in allowlist (not shown here)
if isPrivateIP(ip) {
return false
}
}
return allowlist[host]
}
// Vulnerable pattern: directly uses user-provided URL without validation
func fetchVulnerable(target string) (*http.Response, error) {
return http.Get(target)
}
// Safe pattern: validates and enforces controls before outbound request
func fetchSafe(target string) (*http.Response, error) {
if !isAllowedTarget(target) {
return nil, errors.New("host not allowed")
}
u, err := url.Parse(target)
if err != nil {
return nil, err
}
// Allow only http/https
if u.Scheme != "http" && u.Scheme != "https" {
return nil, errors.New("unsupported scheme")
}
transport := &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: (&net.Dialer{
Timeout: 5 * time.Second,
KeepAlive: 30 * time.Second,
}).DialContext,
TLSClientConfig: &tls.Config{InsecureSkipVerify: false},
}
client := &http.Client{
Transport: transport,
Timeout: 5 * time.Second,
CheckRedirect: func(req *http.Request, via []*http.Request) error {
// Do not follow redirects to avoid SSRF to unintended destinations
if len(via) > 0 {
return http.ErrUseLastResponse
}
return nil
},
}
return client.Get(target)
}
func vulnerableHandler(c *gin.Context) {
target := c.Query("target")
if target == "" {
c.String(400, "target is required")
return
}
resp, err := fetchVulnerable(target)
if err != nil {
c.String(500, err.Error())
return
}
defer resp.Body.Close()
b, _ := io.ReadAll(resp.Body)
c.String(resp.StatusCode, string(b))
}
func safeHandler(c *gin.Context) {
target := c.Query("target")
if target == "" {
c.String(400, "target is required")
return
}
resp, err := fetchSafe(target)
if err != nil {
c.String(400, err.Error())
return
}
defer resp.Body.Close()
b, _ := io.ReadAll(resp.Body)
c.String(resp.StatusCode, string(b))
}
func main() {
r := gin.Default()
r.GET("/vuln", vulnerableHandler) // vulnerable usage
r.GET("/fix", safeHandler) // fixed usage
r.Run(":8080")
}