Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions before 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of CONTINUATION frames even after exceeding Envoy's header map limits. This allows an malicious user to send a sequence of CONTINUATION frames without the END_HEADERS bit set causing CPU utilization, consuming approximately 1 core per 300Mbit/s of traffic and culminating in denial of service through CPU exhaustion. Users should upgrade to version 1.29.3, 1.28.2, 1.27.4, or 1.26.8 to mitigate the effects of the CONTINUATION flood. As a workaround, disable HTTP/2 protocol for downstream connections.
New HTTP/2 DoS attack can crash web servers with a single connection By Bill Toulas April 4, 2024 11:28 AM 0 Newly discovered HTTP/2 protocol vulnerabilities called "CONTINUATION Flood" can lead to denial of service (DoS) attacks, crashing web servers with a single TCP connection in some implementations. HTTP/2 is an update to the HTTP protocol standardized in 2015, designed to improve web performance by introducing binary framing for efficient data transmission, multiplexing to allow multiple r...
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