kali834x opened a new pull request, #803:
URL: https://github.com/apache/commons-compress/pull/803

   framedlz4compressorinputstream.nextblock and 
framedsnappycompressorinputstream.readnextblock advance past zero-output units 
by recursing rather than looping: nextblock reaches an lz4 endmark and calls 
init, which reads the next frame and calls nextblock again, once per empty 
concatenated frame; readnextblock calls itself again after every snappy 
stream-identifier and padding/skippable chunk. those units are all legal per 
the respective frame specs, so the recursion depth is just the 
attacker-controlled count of them. a stream of a few hundred kb of empty frames 
or padding chunks overflows the stack with stackoverflowerror out of read and 
the framedlz4 constructor, which declare only throws ioexception, so a caller 
catching ioexception to handle a corrupt stream gets an error instead. both 
paths are turned into a while loop that advances over the empty units without 
growing the stack; valid streams decode exactly as before. regression tests in 
both decoders build ~200k empty units 
 and assert the stream now reads to eof.
   
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