Buffer Overflow Vulnerability in libsmb2 by Sahlberg

CVE-2025-57632

What is CVE-2025-57632?

The libsmb2 library, versions 6.2 and above, contains a buffer overflow vulnerability related to the processing of SMB2 chained PDUs. This issue arises when the library calls smb2_add_iovector(), which appends data to a fixed-size iovec array without proper boundary checks for the number of I/O vectors. An adversary can exploit this flaw by sending specially crafted responses with numerous chained PDUs, leading to an overflow of the iovec array. Such exploitation may result in memory corruption, application crashes, and could potentially allow unauthorized execution of arbitrary code. Furthermore, the vulnerability also presents a risk during the SMB2_OPLOCK_BREAK path by circumventing message ID validation.

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