A major outage at internet infrastructure firm Cloudflare on November 18, 2025, caused widespread disruptions to thousands of websites and online services globally, underscoring the concentration of risk in core internet platforms. The company acknowledged the problem, stating it was investigating an issue which potentially “impacts multiple customers”1. The incident, which began around 11:30 GMT, resulted in users encountering “Internal server error on Cloudflare’s network” messages when attempting to access affected sites2, including major platforms like X (formerly Twitter) and Letterboxd4.
Timeline and Immediate Impact
The service disruption began at approximately 11:30 GMT/UTC, with Cloudflare first acknowledging the problem on its official status dashboard at 11:48 UTC1. The initial status update carefully noted the company was “aware of, and investigating an issue which potentially impacts multiple customers,” reflecting the early stage of their diagnostic process. Shortly after 12:00 GMT, Cloudflare provided a subsequent update confirming the investigation was ongoing but without identifying a root cause or providing an estimated resolution time1. The outage monitoring service Downdetector itself experienced accessibility issues during this period, demonstrating the cascading nature of the failure and showing a dramatic spike in problem reports from users globally2. This created a compound monitoring challenge for many organizations that rely on external status services to validate their own service availability.
Technical Scope and User Experience
The technical nature of the outage was specified as affecting Cloudflare’s “global network services” according to the company’s status page5. This broad categorization points to a fundamental problem within Cloudflare’s core infrastructure rather than a localized or regional issue. Users attempting to access services protected by or routed through Cloudflare’s network were met with a consistent error message: “Internal server error on Cloudflare’s network” with a suggestion to “please try again in a few minutes”2. This specific error indicates that requests were reaching Cloudflare’s infrastructure but failing to be processed correctly, preventing legitimate traffic from reaching origin servers. The social media platform X and film review service Letterboxd were among the specifically confirmed affected services4, though the impact appeared to extend to a much broader range of websites and online applications given Cloudflare’s market position as a critical infrastructure provider.
Broader Infrastructure Context and Dependencies
This Cloudflare disruption occurs roughly one month after a similar major outage at Amazon Web Services that “knocked more than 1,000 sites and apps offline”1, highlighting a pattern of fragility in internet infrastructure concentrated among a few key providers. Cloudflare provides critical, often invisible, backend infrastructure for millions of websites, including protection from distributed denial-of-service attacks and content delivery network services. Its architecture is designed to absorb and mitigate traffic spikes and malicious activity, but when the core platform experiences problems, it creates a cascading failure effect that takes down a wide array of seemingly unconnected sites2. This dependency creates single points of failure in what is often perceived as a distributed and resilient system, with many organizations relying on the same underlying infrastructure despite having diverse technical stacks and hosting arrangements.
Operational Response and Communication
Cloudflare’s response followed standard incident management protocols for infrastructure providers, with regular updates posted to their status page throughout the investigation. The communication cadence and phrasing reflected a cautious approach to managing expectations while their engineering teams worked to identify and resolve the underlying technical issue. The company’s status dashboard served as the primary source of truth during the incident, though its accessibility may have been impacted for some users depending on their geographic location and network configuration. Organizations dependent on Cloudflare services had limited mitigation options during the outage, as the failure occurred at the infrastructure level before traffic could reach their own systems. This highlights the importance of having contingency plans for critical services that may depend on third-party infrastructure providers.
| Time (UTC) | Event | Impact Level |
|---|---|---|
| ~11:30 | Outage begins | Initial service degradation |
| 11:48 | Cloudflare first acknowledges issue | Widespread user reports |
| ~12:00 | Continued investigation confirmed | Multiple major services affected |
The relevance of this incident extends to operational security and business continuity planning. Organizations should evaluate their dependency on single points of failure in their internet-facing architecture and consider implementing failover mechanisms where possible. Monitoring external dependencies requires both technical validation of service health and business process adaptations to respond quickly when third-party infrastructure experiences problems. The concentration of critical internet services among a small number of providers creates systemic risk that must be accounted for in resilience planning.
In conclusion, the Cloudflare outage of November 18, 2025, serves as another reminder of the interconnected nature of modern internet infrastructure and the operational risks associated with dependency on centralized services. The incident affected numerous high-profile websites and services, demonstrating how problems at major infrastructure providers can create widespread disruption. As organizations continue to rely on third-party services for critical functions, developing robust contingency plans and understanding dependency chains becomes increasingly important for maintaining service availability during such incidents.
