An out-of-bounds access flaw was found in zlib, which allows memory corruption when deflating if the input has many distant matches. For some rare inputs with a large number of distant matches , the buffer into which the compressed or deflated data is written can overwrite the distance symbol table which it overlays. This issue results in corrupted output due to invalid distances, which leads to out-of-bound access, corrupting the memory and potentially crashing the application. A security vulnerability was found in zlib. The flaw triggered a heap-based buffer in inflate in the inflate.c function via a large gzip header extra field. This flaw is only applicable in the call inflateGetHeader