CVE-2025-58190
📋 TL;DR
CVE-2025-58190 is a denial-of-service vulnerability in Go's html.Parse function that causes infinite parsing loops when processing specially crafted HTML content. This affects any Go application using golang.org/x/net/html to parse untrusted HTML input, potentially allowing attackers to crash services.
💻 Affected Systems
- Go applications using golang.org/x/net/html package
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to resource exhaustion (CPU/memory) from infinite loops, leading to sustained downtime.
Likely Case
Service degradation or crashes affecting availability when attackers send malicious HTML payloads.
If Mitigated
Limited impact with proper input validation, rate limiting, and resource constraints in place.
🎯 Exploit Status
Attack requires sending specially crafted HTML to vulnerable parsing endpoint
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to latest golang.org/x/net/html package
Vendor Advisory: https://pkg.go.dev/vuln/GO-2026-4441
Restart Required: Yes
Instructions:
1. Update Go modules: go get -u golang.org/x/net/html
2. Rebuild and redeploy application
3. Restart affected services
🔧 Temporary Workarounds
Input validation and sanitization
allValidate and sanitize HTML input before parsing
Resource limiting
allImplement timeouts and resource limits on HTML parsing operations
🧯 If You Can't Patch
- Implement strict input validation to reject suspicious HTML patterns
- Deploy WAF rules to block malicious HTML payloads before reaching application
🔍 How to Verify
Check if Vulnerable:
Check go.mod for golang.org/x/net/html version and compare with patched versionCheck Version:
go list -m golang.org/x/net/htmlVerify Fix Applied:
Verify updated package version and test with known malicious HTML samples📡 Detection & Monitoring
Log Indicators:
- High CPU usage spikes
- Application crashes during HTML parsing
- Request timeouts on HTML endpoints
Network Indicators:
- Repeated HTML payloads to parsing endpoints
- Unusually large HTML content
SIEM Query:
source="application.logs" AND ("html.Parse" OR "parsing loop") AND (cpu_usage>90 OR status="crash")