Fixed bug (PHP-FPM oob R/W in root process leading to privilege escalation) (CVE-2021-21703).
A memory leak flaw was found in Apache Tomcat, where an HTTP upgrade connection does not release for WebSocket connections once the WebSocket connection is closed. If a sufficient number of such requests are made, an OutOfMemoryError occurs, leading to a denial of service. The highest threat from this vulnerability is to system availability.
Impact The Snappy frame decoder function doesn't restrict the chunk length which may lead to excessive memory usage. Beside this it also may buffer reserved skippable chunks until the whole chunk was received which may lead to excessive memory usage as well.
This vulnerability can be triggered by supplying malicious input that decompresses to a very big size (via a network stream or a file) or by sending a huge skippable chunk.
Impact
All users of SnappyFrameDecoder are affected and so the application may be in risk for a DoS attach due excessive memory usage.
References https://github.com/netty/netty/blob/netty-4.1.67.Final/codec/src/main/java/io/netty/handler/codec/compression/SnappyFrameDecoder.java#L79 https://github.com/netty/netty/blob/netty-4.1.67.Final/codec/src/main/java/io/netty/handler/codec/compression/SnappyFrameDecoder.java#L171 https://github.com/netty/netty/blob/netty-4.1.67.Final/codec/src/main/java/io/netty/handler/codec/compression/SnappyFrameDecoder.java#L185
Impact The Bzip2 decompression decoder function doesn't allow setting size restrictions on the decompressed output data (which affects the allocation size used during decompression).
All users of Bzip2Decoder are affected. The malicious input can trigger an OOME and so a DoS attack
Workarounds No workarounds other than not using the Bzip2Decoder
References
Relevant code areas:
https://github.com/netty/netty/blob/netty-4.1.67.Final/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Decoder.java#L80 https://github.com/netty/netty/blob/netty-4.1.67.Final/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Decoder.java#L294 https://github.com/netty/netty/blob/netty-4.1.67.Final/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Decoder.java#L305