h2: continuation flood cause degradation of service (#1930)

crates/h2/RUSTSEC-0000-0000.md

@@ -0,0 +1,24 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "h2"
+date = "2024-04-03"
+references = ["https://seanmonstar.com/blog/hyper-http2-continuation-flood/"]
+categories = ["denial-of-service"]
+keywords = ["http", "http2", "h2"]
+
+[versions]
+patched = ["^0.3.26", ">= 0.4.4"]
+```
+
+# Degradation of service in h2 servers with CONTINUATION Flood
+
+An attacker can send a flood of CONTINUATION frames, causing `h2` to process them indefinitely.
+This results in an increase in CPU usage.
+
+Tokio task budget helps prevent this from a complete denial-of-service, as the server can still
+respond to legitimate requests, albeit with increased latency.
+
+More details at "https://seanmonstar.com/blog/hyper-http2-continuation-flood/.
+
+Patches available for 0.4.x and 0.3.x versions.