{"schema_version": "1.6.1", "id": "CVE-2026-47321", "summary": "Unbounded Decompression Amplification DoS in Zlib.inflate", "details": "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.\n\nSome compressed data may have a compression ration greater than 1 thousand, leading to an exhaustion of the application memory, as we don't control the deflated size.\n\n\n\n\nThe 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)\n\n\n\n\nFor application using this feature, it is highly recommended to create the CompressionFilter and to pass the maximum limit as a forth constructor parameter, maxDecompressedSize:\n\n\n\n\npublic 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.\n\n\n\n\nHere are the additional constructor:\n\n\n\n\n\n\npublic CompressionFilter(final boolean compressInbound, final boolean compressOutbound,\n\n\n\n            final int compressionLevel, final int maxDecompressedSize,\n\n\n\n            final long maxDecompressRatio, final long decompressRatioMinSize)\n\n\n\n\n\n\n\n\nAlso note that a fluent API has been added to spare the users the pain to call a constructor with that many parameters:\n\n\n\n\n\n\n CompressionFilter compressionFilter = new CompressionFilter()\n\n                                                .setCompressionLevel(Zlib.COMPRESSION_MAX)\n\n                                                .setMaxDecompressedSize(1_000_000)\n\n                                                .setMaxDecompressRatio(100).\n\n                                                .setDecompressRatioMinSize(100_000); \n\n\n\n\n\n\n\n\n\nApplications using Apache MINA are advised to upgrade and configure their CompressionFilter instance.", "affected": [{"ranges": [{"type": "SEMVER", "events": [{"introduced": "2.2.0"}, {"fixed": "2.2.8"}]}, {"type": "SEMVER", "events": [{"introduced": "2.1.0"}, {"fixed": "2.1.13"}]}, {"type": "SEMVER", "events": [{"introduced": "2.0.0"}, {"fixed": "2.0.29"}]}]}], "references": [{"type": "WEB", "url": "https://lists.apache.org/thread/y7xj1bl8qo47p9bktb11hg5v6k1d4dyj"}]}