CVE-2023-25564: GSS-NTLMSSP vulnerable to memory corruption when decoding UTF16 strings

GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, memory corruption can be triggered when decoding UTF16 strings. The variable outlen was not initialized and could cause writing a zero to an arbitrary place in memory if ntlmstrconvert() were to fail, which would leave outlen uninitialized. This can lead to a denial of service if the write hits unmapped memory or randomly corrupts a byte in the application memory space. This vulnerability can trigger an out-of-bounds write, leading to memory corruption. This vulnerability can be triggered via the main gssacceptseccontext entry point. This issue is fixed in version 1.2.0.