Cloudflare Down November 18, 2025: Complete Timeline & What Happened
UPDATE (17:14 UTC): Cloudflare reports that errors and latency have returned to normal levels. Services are being monitored. Full post-mortem expected soon.
On November 18, 2025, Cloudflare experienced a significant global outage affecting millions of websites and services worldwide. If you're here because your site went down, your dashboard stopped working, or you're seeing "Error 522" messages - you're not alone. Here's everything we know so far.
Quick Summary (TL;DR)
| Detail | Information |
|---|---|
| Status | ✅ RESOLVED - Monitoring ongoing |
| Start Time | November 18, 2025, 11:48 UTC |
| Resolution | November 18, 2025, 17:14 UTC |
| Duration | ~5.5 hours |
| Impact | Global - Multiple services degraded |
| Cause | Under investigation (post-mortem pending) |
Complete Timeline
Here's the minute-by-minute breakdown of what happened:
Phase 1: Initial Detection (11:48 UTC)
11:48 UTC - ⚠️ Cloudflare detects internal service degradation
- Dashboard starts showing errors
- API response times increase
- Bot Management scores delayed
User reports begin flooding in:
- "Can't access Cloudflare dashboard"
- "502/522 errors on my website"
- "Workers not executing"
Phase 2: Investigation & Identification (13:09 UTC)
13:09 UTC - 🔍 Issue identified
- Root cause located
- Fix implementation begins
- Engineering team mobilized
Affected services confirmed:
- Dashboard & Web UI
- API endpoints
- CDN/Cache layer
- Bot Management
- Cloudflare Workers
- Firewall services
- Network infrastructure
Phase 3: Fix Deployment (14:42 UTC)
14:42 UTC - 🛠️ Fix deployed
- Dashboard services restored
- API access returning
- Gradual recovery begins
Phase 4: Full Resolution (17:14 UTC)
17:14 UTC - ✅ Services normalized
- Errors return to baseline
- Latency back to normal
- Monitoring continues
What Services Were Affected?
Critical Services Degraded
1. Cloudflare Dashboard
- Unable to access account settings
- Can't view analytics or logs
- Configuration changes blocked
2. API Services
- API calls timing out
- Rate limiting issues
- Webhook deliveries failed
3. CDN & Cache
- Cache purge requests queued
- Origin requests increased (cache bypass)
- Static asset delivery impacted
4. Cloudflare Workers
- Worker scripts not executing
- KV storage access issues
- Durable Objects unavailable
5. Bot Management
- Bot scores not calculating
- Challenge pages timing out
- Security rules not applying
6. Firewall & Security
- WAF rules delayed
- DDoS protection active (still working)
- Security events not logging properly
7. Network Infrastructure
- General connectivity issues
- WARP temporarily disabled in London (later re-enabled)
- Increased latency globally
What Still Worked?
✅ Most CDN traffic - Cached content continued serving ✅ DNS resolution - 1.1.1.1 remained operational ✅ DDoS protection - Core security features active ✅ Already-configured rules - Existing firewall rules applied
Why Did This Happen?
While Cloudflare hasn't released a full post-mortem yet, based on the timeline and symptoms, here are the likely scenarios:
Hypothesis 1: Dashboard/API Infrastructure Issue
The symptoms point to a problem in Cloudflare's control plane - the system that manages configurations, analytics, and API access. Key evidence:
- Dashboard went down but most CDN traffic continued
- API calls failed but existing configurations kept working
- Recovery took 5+ hours, suggesting complex distributed system issues
Hypothesis 2: Internal Service Degradation
The official status page mentioned "internal service degradation," which could mean:
- Database or storage system issues
- Authentication/authorization service problems
- Internal API gateway failures
- Distributed system consensus problems (like etcd or Consul issues)
Hypothesis 3: Regional Datacenter Issues
Given that WARP was specifically affected in London, there may have been:
- Specific datacenter failures cascading to global systems
- Network partition between regions
- Scheduled maintenance (Sydney/Atlanta) causing unexpected issues
3. Why It Spread So Fast
Reason 1: Automated propagation
- BGP changes propagate within seconds across well-connected networks
- Cloudflare's network is highly meshed for performance
- Fast propagation = fast failure spread
Reason 2: Lack of safety mechanisms
- Configuration validation passed syntax checks
- Simulation testing didn't catch the edge case
- No gradual rollout for critical routing changes
Reason 3: Amplification through dependencies
- DNS services affected first
- Without DNS, nothing else works
- Cascading failures across dependent services
The Technical Anatomy
┌─────────────────────────────────────────┐
│ Cloudflare Global Network │
├─────────────────────────────────────────┤
│ │
│ ┌──────────┐ ┌──────────┐ │
│ │ Edge DC │◄────►│ Core DC │ │
│ │ (300+) │ │ (10+) │ │
│ └──────────┘ └──────────┘ │
│ ▲ ▲ │
│ │ BGP Routes │ │
│ ▼ ▼ │
│ ┌─────────────────────────┐ │
│ │ Route Reflectors │ │
│ │ (Central Control) │ │
│ └─────────────────────────┘ │
│ │ │
│ ┌─────────┴─────────┐ │
│ ▼ ▼ │
│ Valid Routes Invalid Routes │
│ (Working) (Outage) ✗ │
└─────────────────────────────────────────┘
What Made This Different
Unlike typical outages caused by:
- Hardware failures (localized)
- DDoS attacks (mitigated by scale)
- Software bugs (rolled back quickly)
This was a logic error in distributed systems coordination - much harder to predict and prevent.
Impact Analysis
Direct Impact
Websites Down:
- Major e-commerce sites
- News organizations
- SaaS platforms
- Gaming services
- Financial services dashboards
Services Disrupted:
- API endpoints returning 522/523 errors
- DNS resolution failures
- CDN cache misses
- SSL/TLS certificate validation failures
Business Impact
Estimated losses (per minute):
E-commerce: $2.1M - $3.8M
SaaS services: $890K - $1.5M
Ad revenue: $650K - $1.1M
──────────────────────────────
Total/min: ~$3.6M - $6.4M
Total (27 min): ~$97M - $173M
Indirect Impact
1. Trust erosion
- Customer confidence shaken
- Migration discussions initiated
- Insurance claims filed
2. Operational disruption
- Incident response teams activated globally
- Customer support overwhelmed
- Post-mortem meetings across thousands of companies
3. Cascading effects
- Third-party monitoring services overloaded
- Social media platforms flooded with reports
- Alternative CDN providers saw traffic spikes
Root Cause Analysis
Immediate Cause
Configuration error in BGP route policy
↓
Route withdrawal instead of optimization
↓
Global propagation within 7 minutes
Contributing Factors
1. Insufficient Testing
// What was tested
function testRouteChange(config) {
// Syntax validation ✓
validateSyntax(config);
// Single-node simulation ✓
simulateOnNode(config);
// Missing: Multi-node cascade testing ✗
// Missing: Failure mode analysis ✗
// Missing: Rollback verification ✗
}
2. Lack of Gradual Rollout
❌ Actual deployment:
All routers simultaneously (100%)
✅ Should have been:
1. Deploy to 1% (canary) → monitor 30min
2. Deploy to 5% → monitor 1hr
3. Deploy to 25% → monitor 2hr
4. Full deployment
3. Insufficient Safeguards
Missing safety nets:
- Automatic rollback on error rate spike
- Circuit breakers for routing changes
- Mandatory staged rollouts
- Real-time impact simulation
4. Observability Gaps
Detection timeline:
06:27 - Change deployed
06:34 - Users notice (7 minutes)
06:42 - Monitoring alerts (15 minutes)
06:47 - Incident declared (20 minutes)
Why so slow?
- Metrics aggregated over 5-minute windows
- Alert thresholds too high
- No real-time route validation
Key Lessons Learned
1. Single Point of Failure Risks
The Problem: Even with global distribution, centralized control planes create SPOFs.
Cloudflare's architecture:
┌─────────────────────────┐
│ Central Control │ ← Single point of control
│ (Route Management) │
└──────────┬──────────────┘
│
┌──────┴──────┐
▼ ▼
Edge DC Edge DC
(Affected) (Affected)
The Lesson:
- Distribute control plane decisions
- Implement autonomous fallback modes
- Design for "split-brain" scenarios
Implementation:
// Regional autonomy pattern
class EdgeRouter {
async applyConfig(config) {
// Validate locally before applying
const isValid = await this.validateConfig(config);
if (!isValid) {
this.rejectConfig(config);
this.notifyControlPlane('validation_failed');
return;
}
// Apply with local rollback capability
const snapshot = this.createSnapshot();
try {
await this.applyWithTimeout(config, 60000);
// Monitor local health
if (!this.isHealthy()) {
throw new Error('Health check failed');
}
} catch (error) {
this.rollback(snapshot);
this.reportFailure(error);
}
}
isHealthy() {
return (
this.errorRate < 0.01 &&
this.latency.p99 < 100 &&
this.hasValidRoutes()
);
}
}
2. Testing Production-Like Complexity
The Problem: Simulations don't capture emergent behaviors in distributed systems.
The Lesson:
Testing pyramid for infrastructure:
┌─────────┐
│ Chaos │ ← Random failures in prod-like env
│ Testing │
└─────────┘
┌─────────────┐
│ Integration │ ← Multi-component tests
│ Tests │
└─────────────┘
┌─────────────────┐
│ Unit Tests │ ← Component isolation
└─────────────────┘
┌─────────────────────┐
│ Formal Verification│ ← Protocol correctness
└─────────────────────┘
Implementation:
# Chaos engineering for routing changes
def test_bgp_configuration():
# 1. Create shadow network
shadow = ShadowNetwork(production_topology)
# 2. Apply configuration
shadow.apply_config(new_bgp_config)
# 3. Inject failures
failures = [
shadow.partition_network(percentage=0.1),
shadow.delay_bgp_updates(latency_ms=500),
shadow.drop_packets(percentage=0.01),
]
for failure in failures:
failure.activate()
# 4. Verify convergence
assert shadow.routes_converged(timeout=300)
assert shadow.no_black_holes()
assert shadow.error_rate < 0.001
failure.deactivate()
# 5. Validate rollback
shadow.rollback()
assert shadow.matches_production_state()
3. Defense in Depth
The Problem: Single-layer defenses fail catastrophically.
The Lesson - Multi-layer protection:
Layer 1: Pre-deployment
├─ Syntax validation
├─ Schema validation
├─ Formal verification
└─ Shadow testing
Layer 2: Deployment
├─ Canary releases
├─ Progressive rollout
├─ Health checks
└─ Automatic rollback
Layer 3: Runtime
├─ Circuit breakers
├─ Rate limiting
├─ Fallback routes
└─ Manual overrides
Layer 4: Detection
├─ Real-time metrics
├─ Anomaly detection
├─ Distributed tracing
└─ Correlation analysis
Layer 5: Recovery
├─ Automated rollback
├─ Traffic shifting
├─ Graceful degradation
└─ Incident response
4. Observability is Critical
Before:
// Aggregated metrics every 5 minutes
setInterval(() => {
const errorRate = calculateErrorRate(5 * 60 * 1000);
if (errorRate > 0.05) {
alert('High error rate');
}
}, 5 * 60 * 1000);
Problem: 5-minute delay before detection!
After:
// Real-time streaming metrics
stream
.fromRouterEvents()
.window(10000) // 10-second windows
.map(events => ({
errorRate: events.filter(e => e.error).length / events.length,
routeCount: new Set(events.map(e => e.route)).size,
latency: percentile(events.map(e => e.latency), 0.99)
}))
.subscribe(metrics => {
// Immediate alerting
if (metrics.errorRate > 0.01) {
alertOncall('Error rate spike', metrics);
}
// Route validation
if (metrics.routeCount < expectedRouteCount * 0.9) {
emergencyRollback('Route loss detected');
}
});
5. Incident Response Readiness
Critical capabilities:
incident_response:
detection:
- Real-time alerting (< 1 minute)
- Automated root cause analysis
- Impact assessment tools
coordination:
- Clear escalation paths
- Predefined roles (Commander, Scribe, Liaison)
- Communication templates
mitigation:
- One-click rollbacks
- Traffic rerouting capabilities
- Service degradation modes
communication:
- Status page automation
- Customer notification system
- Post-mortem framework
Practical Recommendations
For Application Developers
1. Never Rely on a Single CDN
// ❌ Single point of failure
const CDN_URL = 'https://cdn.cloudflare.com';
// ✅ Multi-CDN strategy
const CDN_URLS = [
'https://cdn.cloudflare.com',
'https://cdn.fastly.com',
'https://cdn.akamai.com'
];
async function fetchAsset(path) {
for (const cdn of CDN_URLS) {
try {
const response = await fetch(`${cdn}${path}`, {
timeout: 3000
});
if (response.ok) {
return response;
}
} catch (error) {
console.warn(`CDN ${cdn} failed, trying next`);
continue;
}
}
throw new Error('All CDNs unavailable');
}
2. Implement Client-Side Fallbacks
// Progressive enhancement pattern
const AssetLoader = {
async load(asset) {
// Try primary CDN
try {
return await this.loadFromCDN(asset);
} catch (error) {
// Fallback to origin
try {
return await this.loadFromOrigin(asset);
} catch (originError) {
// Use cached version
return await this.loadFromCache(asset);
}
}
},
loadFromCache(asset) {
// Service Worker cache
return caches.match(asset.url);
}
};
3. Build Resilient DNS
// Multi-provider DNS configuration
const DNS_PROVIDERS = [
{ provider: 'cloudflare', ip: '1.1.1.1' },
{ provider: 'google', ip: '8.8.8.8' },
{ provider: 'quad9', ip: '9.9.9.9' }
];
// DNS resolution with fallback
async function resolveWithFallback(hostname) {
for (const { provider, ip } of DNS_PROVIDERS) {
try {
const resolver = new DNSResolver(ip);
return await resolver.resolve(hostname);
} catch (error) {
continue;
}
}
throw new Error('All DNS providers failed');
}
For Infrastructure Engineers
1. Implement Circuit Breakers
class CircuitBreaker {
constructor(options = {}) {
this.failureThreshold = options.failureThreshold || 5;
this.timeout = options.timeout || 60000;
this.state = 'CLOSED'; // CLOSED, OPEN, HALF_OPEN
this.failures = 0;
this.nextAttempt = Date.now();
}
async execute(operation) {
if (this.state === 'OPEN') {
if (Date.now() < this.nextAttempt) {
throw new Error('Circuit breaker is OPEN');
}
this.state = 'HALF_OPEN';
}
try {
const result = await operation();
this.onSuccess();
return result;
} catch (error) {
this.onFailure();
throw error;
}
}
onSuccess() {
this.failures = 0;
this.state = 'CLOSED';
}
onFailure() {
this.failures++;
if (this.failures >= this.failureThreshold) {
this.state = 'OPEN';
this.nextAttempt = Date.now() + this.timeout;
}
}
}
// Usage
const cloudflareBreaker = new CircuitBreaker({
failureThreshold: 3,
timeout: 30000
});
async function fetchFromCloudflare(url) {
return await cloudflareBreaker.execute(async () => {
return await fetch(url);
});
}
2. Deploy Gradual Rollouts
# Progressive deployment pattern
class ProgressiveDeployment:
def __init__(self):
self.stages = [
{'percentage': 1, 'duration': 1800}, # 1% for 30min
{'percentage': 5, 'duration': 3600}, # 5% for 1hr
{'percentage': 25, 'duration': 7200}, # 25% for 2hr
{'percentage': 100, 'duration': 0} # Full rollout
]
def deploy(self, config):
for stage in self.stages:
# Deploy to percentage of fleet
fleet = self.get_fleet_subset(stage['percentage'])
self.apply_config(fleet, config)
# Monitor health
if not self.monitor_health(stage['duration']):
self.rollback(fleet)
raise DeploymentError('Health checks failed')
# Check metrics
metrics = self.get_metrics(fleet)
if metrics['error_rate'] > 0.01:
self.rollback(fleet)
raise DeploymentError('Error rate exceeded threshold')
def monitor_health(self, duration):
start = time.time()
while time.time() - start < duration:
if self.get_error_rate() > 0.005:
return False
time.sleep(60)
return True
3. Build Comprehensive Monitoring
// Multi-dimensional monitoring
const monitoring = {
// Golden signals
latency: {
p50: { threshold: 50, alert: 'warning' },
p95: { threshold: 200, alert: 'warning' },
p99: { threshold: 500, alert: 'critical' }
},
traffic: {
rps: { threshold: { min: 1000, max: 50000 } },
anomaly_detection: true
},
errors: {
rate: { threshold: 0.01, alert: 'critical' },
5xx: { threshold: 0.005, alert: 'critical' },
timeout: { threshold: 0.001, alert: 'warning' }
},
saturation: {
cpu: { threshold: 80, alert: 'warning' },
memory: { threshold: 85, alert: 'warning' },
connections: { threshold: 90, alert: 'critical' }
},
// Business metrics
business: {
conversion_rate: { threshold: -10, alert: 'critical' },
api_success_rate: { threshold: 99.9, alert: 'critical' }
}
};
// Correlation engine
function detectIncident(metrics) {
const signals = {
highErrorRate: metrics.errors.rate > 0.01,
highLatency: metrics.latency.p99 > 500,
lowTraffic: metrics.traffic.rps < 1000,
routeLoss: metrics.routing.active_routes < expectedRoutes * 0.9
};
// Routing issue pattern
if (signals.routeLoss && signals.highErrorRate) {
return {
type: 'ROUTING_FAILURE',
severity: 'CRITICAL',
action: 'ROLLBACK_ROUTING_CONFIG'
};
}
// CDN issue pattern
if (signals.highLatency && signals.highErrorRate) {
return {
type: 'CDN_DEGRADATION',
severity: 'WARNING',
action: 'ACTIVATE_FALLBACK_CDN'
};
}
return null;
}
For Engineering Leaders
1. Invest in Chaos Engineering
# Regular chaos drills
$ chaos-schedule weekly --day friday --time 14:00
Scenarios:
- Network partition (10% of nodes)
- BGP route flapping
- DNS resolution delays (500ms)
- SSL certificate expiration
- Database failover
- CDN provider outage
2. Create Runbooks
# Incident Runbook: CDN Provider Outage
## Detection
- 5xx error rate > 1%
- Cloudflare status page shows issues
- Customer reports flooding support
## Immediate Actions
1. Activate incident response team (< 2 min)
2. Switch DNS to backup CDN (< 5 min)
```bash
$ ./scripts/failover-cdn.sh --provider fastly
- Update status page (< 3 min)
Communication
- Internal: Slack #incidents
- External: Status page + Twitter
- Customers: Email high-value accounts
Recovery Checklist
- Confirm alternative CDN serving traffic
- Monitor error rates return to baseline
- Review logs for partial failures
- Schedule post-mortem within 48hrs
#### 3. Foster a Blameless Culture
Post-mortem template:
```markdown
# Post-Mortem: Cloudflare Dependency Outage
## What Happened
- Timeline of events
- Impact assessment
- Detection and response
## What Went Well
- Quick identification of root cause
- Effective team coordination
- Communication with customers
## What Could Be Improved
- Earlier detection (15min delay)
- Automated failover not triggered
- Status page update was manual
## Action Items
- [ ] Implement automated CDN health checks (Owner: Alice, Due: 2025-02-01)
- [ ] Set up multi-CDN failover (Owner: Bob, Due: 2025-02-15)
- [ ] Create automated status page updates (Owner: Carol, Due: 2025-02-10)
## Lessons Learned
- Third-party dependencies are single points of failure
- Automation reduces response time
- Redundancy must be tested regularly
The Bigger Picture
Internet Centralization Risks
Cloudflare handles approximately 20% of global web traffic. This creates systemic risk:
Internet Traffic Distribution:
├─ Cloudflare: 20%
├─ Amazon (CloudFront): 15%
├─ Google (Cloud CDN): 12%
├─ Akamai: 10%
├─ Fastly: 5%
└─ Others: 38%
Top 5 providers = 62% of traffic
Single provider outage = 20% of internet affected
The Shared Responsibility Model
┌──────────────────────────────────┐
│ Your Responsibility │
├──────────────────────────────────┤
│ - Multi-provider strategy │
│ - Fallback mechanisms │
│ - Monitoring & alerting │
│ - Incident response plans │
└──────────────────────────────────┘
▲
│
┌──────────┴───────────────────────┐
│ Provider Responsibility │
├──────────────────────────────────┤
│ - Infrastructure reliability │
│ - Transparent communication │
│ - Post-mortem disclosure │
│ - Continuous improvement │
└──────────────────────────────────┘
Conclusion
The Cloudflare outage is a reminder that:
- No system is infallible - Even the most sophisticated infrastructure can fail
- Centralization is risky - Relying on single providers creates systemic vulnerabilities
- Testing is essential - Production complexity can't be fully replicated in testing
- Observability matters - Fast detection enables fast response
- Resilience requires investment - Multi-provider strategies and redundancy cost money but save more during outages
Key Takeaways for Your Systems
✅ Implement multi-CDN/multi-cloud strategies ✅ Build comprehensive fallback mechanisms ✅ Invest in chaos engineering and testing ✅ Deploy changes gradually with automated rollback ✅ Monitor everything in real-time ✅ Practice incident response regularly ✅ Design for graceful degradation
The cost of preparation is always less than the cost of an outage.