CVE-2026-47321

The CompressionFilter class uses ZLib to deflate and inflate data sent and received. When we inflate incoming data, the filter does not control the resulting size, and create a buffer no matter what.<br /> <br /> Some compressed data may have a compression ration greater than 1 thousand, leading to an exhaustion of the application memory, as we don&amp;#39;t control the deflated size.<br /> <br /> <br /> <br /> <br /> The fix adds such a control by allowing the application developer to provide a fixed size limit, which when reached throws an exception. It also allows the user to provide a compression ratio that should not be exceeded, protected the application from small inflated files that inflate in gigantic files, but with a grace limit for the resulting size (1Mb) to avoid false positive (like a very small file inflating with a high ratio, but resulting with a acceptable size, like a few thousands bytes)<br /> <br /> <br /> <br /> <br /> For application using this feature, it is highly recommended to create the CompressionFilter and to pass the maximum limit as a forth constructor parameter, maxDecompressedSize:<br /> <br /> <br /> <br /> <br /> public CompressionFilter(final boolean compressInbound, final boolean compressOutbound, final int compressionLevel, final int maxDecompressedSize)Optionally one can also provide a maxDecompressRatio fifth parameter, and a decompressRatioMinSize sixth parameter to allow small inflated files with a high compression ratio to still be accepted.<br /> <br /> <br /> <br /> <br /> Here are the additional constructor:<br /> <br /> <br /> <br /> <br /> <br /> <br /> public CompressionFilter(final boolean compressInbound, final boolean compressOutbound,<br /> <br /> <br /> <br /> final int compressionLevel, final int maxDecompressedSize,<br /> <br /> <br /> <br /> final long maxDecompressRatio, final long decompressRatioMinSize)<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Also note that a fluent API has been added to spare the users the pain to call a constructor with that many parameters:<br /> <br /> <br /> <br /> <br /> <br /> <br />  CompressionFilter compressionFilter = new CompressionFilter()<br /> <br />     .setCompressionLevel(Zlib.COMPRESSION_MAX)<br /> <br />   .setMaxDecompressedSize(1_000_000)<br /> <br />   .setMaxDecompressRatio(100).<br /> <br />   .setDecompressRatioMinSize(100_000); <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Applications using Apache MINA are advised to upgrade and configure their CompressionFilter instance.