Description
zlib is a Ruby interface for the zlib compression/decompression library. Versions 3.0.0 and below, 3.1.0, 3.1.1, 3.2.0 and 3.2.1 contain a buffer overflow vulnerability in the Zlib::GzipReader. The zstream_buffer_ungets function prepends caller-provided bytes ahead of previously produced output but fails to guarantee the backing Ruby string has enough capacity before the memmove shifts the existing data. This can lead to memory corruption when the buffer length exceeds capacity. This issue has been fixed in versions 3.0.1, 3.1.2 and 3.2.3.
Problem types
CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-131: Incorrect Calculation of Buffer Size
Product status
>= 3.1.0, < 3.1.2
>= 3.2.0, < 3.2.3
References
github.com/ruby/zlib/security/advisories/GHSA-g857-hhfv-j68w