On Windows only, if libpcap needs to convert a Windows error message to UTF-8 and the message includes characters that UTF-8 represents using 4 bytes, utf_16le_to_utf_8_truncated() can write data beyond the end of the provided buffer.

pcap_ether_aton() is an auxiliary function in libpcap, it takes a string argument and returns a fixed-size allocated buffer. The string argument must be a well-formed MAC-48 address in one of the supported formats, but this requirement has been poorly documented. If an application calls the function with an argument that deviates from the expected format, the function can read data beyond the end of the provided string and write data beyond the end of the allocated buffer.

Remote packet capture support is disabled by default in libpcap. When a user builds libpcap with remote packet capture support enabled, one of the functions that become available is pcap_findalldevs_ex(). One of the function arguments can be a filesystem path, which normally means a directory with input data files. When the specified path cannot be used as a directory, the function receives NULL from opendir(), but does not check the return value and passes the NULL value to readdir(), which causes a NULL pointer derefence.

In affected libpcap versions during the setup of a remote packet capture the internal function sock_initaddress() calls getaddrinfo() and possibly freeaddrinfo(), but does not clearly indicate to the caller function whether freeaddrinfo() still remains to be called after the function returns. This makes it possible in some scenarios that both the function and its caller call freeaddrinfo() for the same allocated memory block. A similar problem was reported in Apple libpcap, to which Apple assigned CVE-2023-40400.