Server-Side Template Injection (SSTI) Pattern Regex for Go

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching server-side template injection (ssti) pattern, ported and verified for Go. In security-sensitive code, using an unverified regex can open the door to both false positives and denial-of-service attacks. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

// Server-Side Template Injection (SSTI) Pattern
// ReDoS-safe | RegexVault — Security > Injection Patterns

package validation

import "regexp"

var serversideTemplateInjectionSstiPatternRe = regexp.MustCompile(`(?:\{\{[^}]*\}\}|\{%[^%]*%\}|\$\{[^}]*\}|#\{[^}]*\}|<#[^>]*>|@\{[^}]*\}|\[\[.*?\]\]|\{#[^}]*#\}|\{\{7\*7\}\}|\{\{config\}\}|\{\{self\}\}|__class__|__mro__|__import__)`)

func ValidateServersideTemplateInjectionSstiPattern(s string) bool {
    return serversideTemplateInjectionSstiPatternRe.MatchString(s)
}

// Example
// fmt.Println(ValidateServersideTemplateInjectionSstiPattern("{{7*7}}")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Security > Injection Patterns category and carries a ReDoS-safe certification. That matters for Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Template engines: Jinja2/Twig/Nunjucks use {{ }}, {% %}, Freemarker uses ${}, Ruby ERB uses <%=%>. The probe {{7*7}} (expected result 49) is the canonical SSTI detection test. __class__ and __mro__ are Python object introspection used in Jinja2 sandbox escapes.