static int smb311_decode_neg_context(struct smb2_negotiate_rsp *rsp,
				     struct TCP_Server_Info *server,
				     unsigned int len_of_smb)
{
	struct smb2_neg_context *pctx;
	unsigned int offset = le32_to_cpu(rsp->NegotiateContextOffset);
	unsigned int ctxt_cnt = le16_to_cpu(rsp->NegotiateContextCount);
	unsigned int len_of_ctxts, i;
	int rc = 0;

	cifs_dbg(FYI, "decoding %d negotiate contexts\n", ctxt_cnt);
	if (len_of_smb <= offset) {
		cifs_dbg(VFS, "Invalid response: negotiate context offset\n");
		return -EINVAL;
	}

	len_of_ctxts = len_of_smb - offset;

	for (i = 0; i < ctxt_cnt; i++) {
		int clen;
		/* check that offset is not beyond end of SMB */
		if (len_of_ctxts == 0)
			break;

		if (len_of_ctxts < sizeof(struct smb2_neg_context))
			break;

		pctx = (struct smb2_neg_context *)(offset + (char *)rsp);
		clen = le16_to_cpu(pctx->DataLength);
		if (clen > len_of_ctxts)
			break;

		if (pctx->ContextType == SMB2_PREAUTH_INTEGRITY_CAPABILITIES)
			decode_preauth_context(
				(struct smb2_preauth_neg_context *)pctx);
		else if (pctx->ContextType == SMB2_ENCRYPTION_CAPABILITIES)
			rc = decode_encrypt_ctx(server,
				(struct smb2_encryption_neg_context *)pctx);
		else if (pctx->ContextType == SMB2_POSIX_EXTENSIONS_AVAILABLE)
			server->posix_ext_supported = true;
		else
			cifs_dbg(VFS, "unknown negcontext of type %d ignored\n",
				le16_to_cpu(pctx->ContextType));

		if (rc)
			break;
		/* offsets must be 8 byte aligned */
		clen = (clen + 7) & ~0x7;
		offset += clen + sizeof(struct smb2_neg_context);
		len_of_ctxts -= clen;
	}
	return rc;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.