Cloudflare stock falls 3.2% after security flaw disclosure

Shares of Cloudflare dropped 3.2% in afternoon trading after the company revealed a cross-tenant data-isolation vulnerability in its Containers and Sandboxes products. The flaw could have let a customer recover residual disk data previously used by containers belonging to other customers on the same host.

Cloudflare stated that it resolved the issue and found no evidence of compromised customer data or malicious exploitation. After the initial slide, the stock pared losses to close down 2.6% at $348.63. The pullback coincided with broader caution around cybersecurity valuation multiples following an artificial intelligence rally.

The stock has experienced sharp volatility, recording 38 moves greater than 5% over the past year. Four days earlier, shares jumped 6.8% when the benchmark 10-year Treasury yield dropped roughly 3 basis points to 4.97%, easing pressure on software valuations.

Cloudflare also recently rolled out general availability for Python Workers on its global developer platform. The runtime natively supports frameworks such as FastAPI and Django along with AI tools like LangChain, building on management's second-quarter earnings report showing non-human requests now exceed 50% of network traffic.

The company has gained roughly 29% over the past month and is up 77.8% since the start of the year. At $348.63, the stock trades near its 52-week high of $358.82 reached in September 2026.